JP2009097894A - Partial discharge measuring device, method for calibrating the same, and partial discharge measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a partial discharge measuring device capable of performing partial discharge measurement and calibration, without being accompanied by a power failure. <P>SOLUTION: The discharge measuring device for measuring partial discharge occurring in electric equipment, is provided with ring-shaped cores composed of magnetic substances through which partial discharge currents flow, secondary windings wound around the ring-shaped cores, capacitors, and electric-circuit conductor side antennas composed of air core coils. Electric-circuit conductor side device portions composed by forming series resonant circuits of the secondary windings, capacitors, and electric-circuit conductor side antennas, are respectively provided in electric-circuit conductor portions arranged at two or more spots to be capacitively united in electric-circuit conductors. A first electric-circuit conductor side device portion out of those, is used as a simulated partial discharge signal receiving portion, and is made to receive a simulated partial discharge signal simulating partial discharge via the electric-circuit conductor side antenna from outside, and a second electric-circuit conductor side device portion is used as a partial discharge detection portion, and is made to transmit a partial discharge detection signal to the outside via the electric-circuit conductor side antenna. By doing this way, calibration of detection sensitivity on the occasion of using the second electric-circuit conductor side device portion as the partial discharge detection portion becomes possible. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a partial discharge measurement technique for measuring partial discharge in a power device.

  The partial discharge test for electric power equipment is important to ensure the reliability and safety of the equipment, and the partial discharge measurement methods are defined in standards such as IEC, JIS, and JEC. A partial discharge test is conducted based on the test method, and it is confirmed that there is no partial discharge before shipment.

  For example, an electrical device in which a current-carrying part such as a mold transformer is insulated with a mold resin such as an epoxy resin has a characteristic of being strong against moisture and contamination because of its excellent sealing performance, and therefore has a high voltage. Although it is widely used in electric power equipment, the material deteriorates due to thermal or chemical action in the resin part during long-time operation, mechanically hardens and becomes brittle, and electrically There is a problem that the insulation resistance is lowered. Due to these factors, cracks in the resin itself and peeling of the adhesive interface between the resin and the metal part such as a coil that did not occur in the mold resin during long-term operation occurred, which became gaps and caused partial discharge. Cause. Once partial discharge occurs, the gas in the gap changes to radicals due to the discharge reaction, and chemical resin deterioration progresses at an accelerated rate. And it becomes extremely important for safety.

  The partial discharge measurement during operation as described above is performed at the site where the power equipment is installed. The field test differs from the factory test in that the product cannot be divided, the level of various noises such as external power supply and electromagnetic noise from the surroundings is high, and the working space is narrow, and the operation of the power equipment is not stopped. Therefore, it is required to carry out in a short time and at a low cost.

  As for partial discharge measurement, various methods have been proposed and implemented as shown in Non-Patent Document 1, for example. These are methods using current, electric field, magnetic field, electromagnetic field, light, sound, and chemical reaction. Since the standard for partial discharge measurement is based on the quantity of electricity called discharge charge, it is necessary to calibrate the correspondence with the charge in advance by the method using light, sound, and chemical reaction. Depending on the nature of partial discharge, it does not necessarily correspond one-to-one. Even in a method using an electric field, a magnetic field, or an electromagnetic field, the correspondence with the charge amount is not necessarily one-to-one depending on the frequency to be captured. Therefore, although the method of capturing the current is excellent as a quantitative measurement method of partial discharge, it is actually a measurement method that is most susceptible to noise. Non-Patent Document 1 also describes a method of capturing an ultra-high frequency (UHF) electromagnetic wave generated by partial discharge with an antenna in a gas insulated switchgear (GIS).

[Conventional technology for partial discharge measurement]
Among power devices, even in a molded transformer, in order to cope with the case where partial discharge measurement at the installation site as described above is required, configurations such as Patent Documents 1 to 8 have been proposed so far. ing.

  That is, in Patent Document 1, a high-frequency current transformer having a primary conductor as a connection conductor that conductively connects between tap terminals is provided as a partial discharge detection sensor. After amplifying the output signal of this high-frequency current transformer, There is disclosed a partial discharge measuring device configured to convert and transmit a signal to the ground potential side through an optical fiber.

  In Patent Document 2, as proposals for improving the partial discharge measuring device disclosed in Patent Document 1, adjustment of attenuation of an attenuator on the high potential side and switching control of a switch of a battery power supply for supplying power to an amplifier or the like are disclosed. Has been disclosed to remotely control the signal using a signal propagating through the insulating medium from the ground potential side.

  In Patent Document 3, as a proposal for improving the partial discharge measuring device disclosed in Patent Document 1, a detector composed of a through-type current transformer through which a tap connection conductor passes and an amplifying unit are housed on the internal input side. By adopting a connector-to-electric connector connection method, a detector can be laid in advance on the high-potential side tap terminal, and the tap connection conductor can be removed and attached between the tap terminals. A configuration that is unnecessary is disclosed.

  In Patent Document 4, as a proposal for improving the partial discharge measuring device disclosed in Patent Document 1, electric power for charging a battery power supply for supplying power to an amplifier or an electro-optical converter in a partial discharge sensor on the high potential side is disclosed. In other words, a configuration is disclosed in which a power failure operation for charging a battery power supply is eliminated by supplying light or fluid pressure.

Patent Document 5 discloses a method of performing calibration of detection sensitivity without shutting off the power supply in the field as a proposal for improving the partial discharge measuring device disclosed in Patent Document 1.
In Patent Document 6, as an improvement proposal of the partial discharge measuring device disclosed in Patent Document 1, in order to prevent the core of a through-type current transformer for partial discharge detection from being saturated with a current of commercial frequency, Through a low-pass filter that passes through the commercial frequency band at both ends of the filter winding. The structure etc. which connected the load circuit which sends the electric current of a commercial frequency band are disclosed.

  In Patent Document 7, as a proposal for improving the partial discharge measuring device disclosed in Patent Document 1, a through-type current transformer for partial discharge detection is used to remove high-level noise components outside a specific frequency range. A configuration is disclosed in which a filter winding for winding an iron core is provided, and a load circuit is connected to both ends of the filter winding via a filter that blocks signal components in a specific frequency range.

  Patent Document 8 discloses a method for detecting partial discharge of a three-phase transformer winding including a high-voltage winding that is star-connected and has a connection portion with a neutral point located on the outermost periphery. In order not to be affected by the strong electric field generated in the circuit, a configuration in which a loop antenna is placed near the neutral point to capture high-frequency electromagnetic waves caused by partial discharge generated in the high-voltage winding, and Discloses a configuration in which the loop antenna is provided with two loop circuits, and the electromagnetic wave detection output from each loop circuit is subjected to an electric field component canceling process and a magnetic field component doubling process by a differential circuit. ing.

  In addition, as described above, the measurement method for capturing the current flowing through the partial discharge is excellent as a quantitative measurement method for partial discharge in terms of the correspondence with the amount of discharge charge, but is also a method susceptible to noise. For this reason, in the partial discharge measuring apparatus of the type that captures the current, conventionally, the frequency band of the detection signal is limited in order to improve the S / N ratio. 10 proposes the following method.

That is, Patent Document 9 relates to a partial discharge detection method for high-voltage equipment such as a rotating electrical machine, a transformer, and a switchgear, and the frequency component of the high-frequency pulse current generated by the partial discharge is several tens kHz to several hundreds MHz. Although it is distributed over a wide range, this partial discharge pulse current is detected by a through-type high-frequency current transformer whose primary conductor is the ground wire of a high-voltage device. By selecting the tuning frequency of the tuning-type partial discharge measuring device that receives the output for measurement in the range of 1.8 MHz to 3.8 MHz, more preferably in the range of 2.8 to 3.1 MHz, the commutation of the thyristor, etc. It is disclosed that the S / N ratio with respect to external noise such as noise can be increased and the influence of broadcast wave and communication wave noise can be eliminated.

  Patent Document 10 relates to a method and an apparatus for measuring partial discharge of electrical equipment, and the partial discharge current generally includes frequency components in all bands from low frequency components to high frequency components. The limit frequency on the high-frequency side that exists is very high, from several tens of MHz to several hundreds of MHz, although it varies somewhat depending on the form of partial discharge. Such partial discharge current is detected using a current transformer. In this case, a capacitor is connected in parallel to the secondary side of the current transformer in the detection unit, and a resonance circuit is formed by this capacitor and the inductance component of the current transformer, so that the specific current included in the partial discharge current is specified. It has been disclosed that detection of frequency components makes it less susceptible to external noise.

The applicant has also filed Japanese Patent Application No. 2006-263668 (prior application), which relates to a partial discharge detection method for high voltage equipment such as rotating electrical machines, transformers, switchgears, etc. In References 1, 2, 3, and 4, it is necessary to attach a detector to the high-voltage path side for partial discharge measurement. A current transformer that converts current into voltage, a capacitor connected in series to the secondary winding of this current transformer, and a transmission antenna (air-core coil) are provided, and the magnetic field radiated from the transmission antenna is contactlessly provided. An apparatus is disclosed that can measure partial discharges uninterruptibly by a receiving antenna (air core coil) that is detected from the outside and an amplifier that amplifies a received signal from the receiving antenna.

[Configuration example of a partial discharge measuring device according to the prior art]
All of the partial discharge measuring devices disclosed in the above-mentioned Patent Documents 1 to 7 and the prior application (Japanese Patent Application No. 2006-263668) are taps that are current paths of partial discharge currents in a distribution transformer. This is a method of detecting partial discharge current by providing a high-frequency current transformer so that the tap connection conductor that conducts conductive connection between the terminals penetrates, and it is a measurement method that captures the current flowing by partial discharge. This method is excellent in terms of the correspondence between the charge amount and the measurement signal.

  Moreover, in the partial discharge measuring apparatus of the system which captures the electric current as disclosed in Patent Documents 1 to 7 and the prior application (Japanese Patent Application No. 2006-263668), it has been disclosed in Patent Document 9 conventionally. In addition, a measurement method that performs tuned detection in a relatively low frequency band of several MHz is widely used, and Patent Document 10 discloses one configuration for detecting a specific frequency component included in a partial discharge current. As shown in FIG. 1, a detection unit configuration in which a resonance circuit is formed by a capacitor connected in parallel to the secondary side of the current transformer and the inductance component of the current transformer is used.

(Configuration example of conventional partial discharge measuring device)
Next, a configuration example of a conventional partial discharge measuring apparatus in which the above-described conventional technique relating to a partial discharge measuring apparatus of a method for capturing current is applied to a transformer installed in the field will be described below.

  FIG. 15 is a front view showing an external appearance of the three-phase molded transformer and external connection terminals. In FIG. 15, the three-phase molded transformer has a three-phase high-voltage winding 1 (1U, 1V, 1W) connected to each main leg of a three-legged iron core 2 sandwiched between frames 3 and 3a. It is configured to be wound. The high-voltage winding 1 is formed by molding the entire winding conductor with a highly insulating epoxy resin, and the outer shape thereof is substantially cylindrical. A low voltage winding (not shown) is disposed on the inner diameter side of the high voltage winding 1, and this low voltage winding is also wound around each main leg of the iron core 2.

  Each of the three-phase high-voltage windings 1 is provided with high-voltage winding terminals 4 and 4a and voltage switching tap terminals 5 and 5a. The tap terminals 5 and 5a are connected via a tap connection conductor 7 and short-circuited. Has been. The high voltage winding terminals 4 and 4a are connected to each other via high voltage interphase leads 9 (9UV, 9VW, 9WU). The high-voltage interphase leads 9 (9UV, 9VW, 9WU) are collectively resin-molded to form a high-voltage interphase lead connecting portion 6 having an insulating resin block structure. Also, the high-voltage bus terminals 8 (8U, 8V, 8W) of the respective phases are connected to the high-voltage winding terminals 4 (4U, 4V, 4W) of the respective phases serving as the electric circuit connection terminals.

  FIG. 16 is a block diagram of a partial discharge measuring apparatus according to the prior art, and shows a configuration example for the three-phase mold transformer shown in FIG. FIG. 17 is a configuration diagram showing a detailed configuration of a partial discharge detector in the partial discharge measuring apparatus of FIG. Further, FIG. 18 is a diagram showing the connection between the partial discharge measuring device of FIG. 16 and the high-voltage winding of the three-phase mold transformer.

  The partial discharge measuring apparatus shown in FIG. 16 includes a partial discharge detection unit 25 including a detector 10 and an electric-optical converter 20, an optical cable (fiber) 30, an optical-electric converter 41, a main amplifier 42, and a display unit. And a partial discharge receiving unit 45 comprising 43. The optical cable 30 detects partial discharge in a state where the partial discharge detector 25 installed on the high potential side of the mold transformer and the partial discharge receiver 45 installed on the ground potential side are electrically isolated. It is intended to transmit signals.

  As shown in FIG. 17, in the partial discharge detection unit 25, the detector 10 includes a ring-shaped core 11 that circulates a tap connection conductor 7 that is a connection conductor between the tap terminals 5 and 5 a, and the ring-shaped core 11. Are composed of a secondary winding 12 wound in a toroidal shape and a capacitor 13 connected in parallel to both ends of the secondary winding 12, and the ring-shaped core 11 and the secondary winding 12 are composed of a tap connection conductor. A through-type current transformer having a primary conductor 7 is formed.

  In the detector 10, the partial discharge current flowing through the tap connection conductor 7 is converted into a voltage by the feedthrough current transformer, and the capacitor 13 connected in parallel to the secondary winding 12 of the feedthrough current transformer. Thus, a detection signal whose frequency band is limited by resonating at a specific frequency is output from the detector 10.

  The detection signal output from the detector 10 is input to the amplification unit 21 built in the input side of the electro-optical converter 20, and the electric signal output from the amplification unit 21 is output from the electro-optical conversion unit 22. The electric signal converted into an optical signal, transmitted through the optical cable 30, and reconverted by the optical-electrical converter 41 in FIG. 16 is converted into an electric signal having a specification suitable for the display unit 43 connected to the subsequent stage by the main amplifier 42. Measurement is performed on the display unit 43 such as an oscilloscope or a meter based on the obtained signal.

  The partial discharge is measured by attaching one end of the detector 10 and the electro-optical converter 20 and the optical cable 30 in FIG. 17 to the tap terminals 5 and 5a on the high potential side, and connecting the tap connection conductor 7 between the tap terminals 5 and 5a. This is implemented by capturing the pulse current due to the flowing partial discharge on the ground potential side where the measurer is present. The measurer observes the pulse current due to the partial discharge using the display unit 43 such as an oscilloscope or a meter.

FIG. 18 shows a configuration example of the high-voltage side winding of the three-phase mold transformer, and a connection configuration between the high-voltage side winding and the partial discharge measuring device of FIG. That is, in FIG. 18, the high-voltage winding terminals 4U, 4aU, 4V, 4aV, 4W, and 4aW of the three-phase high-voltage windings 1U, 1V, and 1W in the three-phase molded transformer are high-voltage interphase leads 9UV, 9VW, and 9WU. And the voltage switching tap terminals 5U, 5aU, 5V, 5aV, 5W, and 5aW are provided in the high-voltage windings 1U, 1V, and 1W of the respective phases. In FIG. 18, the partial discharge in the high-voltage winding of the three-phase molded transformer is caused by a through-type current transformer in which the tap connection conductor 7 provided in the voltage switching tap terminals 5 and 5 a of each phase is the primary conductor. An electrical signal detected by the secondary winding 12, amplified by the amplification unit 21, converted into an optical signal by the electrical-optical conversion unit 22, transmitted by the optical cable 30, and reconverted by the optical-electrical converter 41, It is shown that the main amplifier 42 amplifies the electrical signal so as to have a specification suitable for the display unit 43 connected to the subsequent stage, and that the obtained signal is measured on the display unit 43 such as an oscilloscope or a meter. .

(Configuration of partial discharge measuring device according to previous application)
As shown in FIG. 19, the partial discharge measuring device of the prior application (Japanese Patent Application No. 2006-263668) has a spatial distance facing the partial discharge detection unit 100 including the detector 110 and the transmission antenna 101 and the transmission antenna 101. The receiving antenna 201, the matching unit 202, the transmission cable 203, the preamplifier 204, the main amplifier 205, and the partial discharge receiving unit 200 including the display unit 206 are provided. FIG. 20 shows a more detailed configuration of the partial discharge detection unit 100 in FIG. Voltage switching tap terminals 5 and 5a are embedded in the high voltage winding 1 molded with epoxy resin in the mold transformer, and a tap connection conductor 7 is provided between the tap terminals 5 and 5a through which the main current of the mold transformer flows. It is attached. A ring-shaped core 11 that goes around the tap connection conductor 7 is provided, and the secondary winding 12 is wound around the ring-shaped core 11 in a toroidal shape, so that the tap connection conductor 7, the ring-shaped core 11, and the secondary core 12 are wound. A through-type current transformer composed of the winding 12 is formed, whereby a partial discharge current flowing through the tap connection conductor 7 can be detected. At both ends of the secondary winding 12, a capacitor 113 and a transmitting antenna 101 that is an air-core coil and includes one or more air-core loop antennas are connected in series. The secondary winding 12 and the capacitor 113 are connected. And a transmitting antenna 101 are formed as a series resonant circuit. In this series resonance circuit, the partial discharge current detected by the feedthrough current transformer serves as an excitation source, mainly the secondary winding 12, the inductances of the transmission antenna 101, and the capacitance (capacitance) of the capacitor 113. LC series resonance occurs at a resonance frequency f 0 determined based on (), and a strong magnetic field is radiated from the transmitting antenna 101. As described above, the resonance frequency f0 is preferably selected from a frequency band of several MHz in order to increase the correlation with the integral value of the partial discharge current, and more specifically within a range of 400 kHz to 10 MHz. It is preferable to select by.

  The ring-shaped core 11, the secondary winding 12, and the capacitor 113 are a detector provided integrally with the tap connection conductor 7, for example, by adopting an insulating resin block structure in which resin molding is collectively performed. 110, the partial discharge detection unit 100 including the detector 110 and the transmission antenna 101 is connected to the tap terminals 5 and 5a with bolts and fixed.

  The ring-shaped core 11 may be made of a material having excellent soft magnetic properties such as ferrite, that is, a material having good BH characteristics and high resistivity. Further, if a mica capacitor or the like is used as the capacitor 113, a very high Q value can be obtained.

  As shown in FIG. 19, the partial discharge receiving unit 200 is an air core coil that is arranged so that the magnetic field radiated from the transmission antenna 101 is interlinked, and includes a reception antenna 201 that includes one or more air core loop antennas. Suitable for display on the matching unit 202 that matches the impedance of the antenna 201 and the impedance of the transmission cable 203, the transmission cable 203, the preamplifier 204 that performs amplification by limiting to a predetermined frequency, and the display unit 206 connected to the subsequent stage. And a display section 206 such as an oscilloscope.

The sensitivity of the receiving antenna 201 increases as the number of turns of the coil increases, and decreases as the capacitance between the conductors forming the coil increases. If the number of turns of the coil is too large, the capacitance between the conductors forming the coil also increases. For this reason, in order to increase the sensitivity of the receiving antenna 201, it is necessary to select an optimal number of turns as a coil.

  The size of the coil of the receiving antenna 201 has an optimum value determined by the distance between the transmitting antenna 101 and the receiving antenna 201 according to the distribution of the magnetic field generated by the transmitting antenna 101.

  The matching unit 202 is a circuit for matching the impedance between the receiving antenna 201 and the transmission cable 203, and a transformer type is usually used at frequencies up to about several MHz. Note that a coaxial cable is usually used as the transmission cable 203.

  Further, the preamplifier 204 performs amplification tuned with a predetermined bandwidth with respect to the same frequency as the resonance frequency f0 in the partial discharge detection unit 100. As the circuit of the preamplifier 204, an amplifier circuit including a passive bandpass filter is used. The narrower the band-pass filter bandwidth, the higher the Q factor, and the better the sensitivity and S / N ratio. The wider the band-pass filter bandwidth, the better the pulsed state of the original partial discharge current. Saved in. For this reason, when selecting the bandwidth of the bandpass filter, it is necessary to consider the above two points. However, by selecting the bandwidth within the range of 10 kHz to 500 kHz, sufficient sensitivity and S / N can be obtained. A ratio can be obtained, and a partial discharge measurement can be performed in a state where the pulsed state of the original partial discharge current is sufficiently preserved.

In the main amplifier 205, for example, an oscilloscope or the like connected to the subsequent stage is detected by detecting the input signal that is a vibration attenuation wave from the preamplifier 204 and outputting it as a unipolar pulse-shaped signal. Observation of the partial discharge current in the display unit 206 is facilitated.
JP-A-3-216564 JP-A-4-259864 JP-A-5-322963 JP-A-7-174811 Japanese Patent Application Laid-Open No. 9-119959 Japanese Patent Laid-Open No. 9-80112 Japanese Patent Laid-Open No. 9-15293 JP-A-3-37580 Japanese Patent Laid-Open No. 2-85771 JP-A-7-12881 Published by the Institute of Electrical Engineers of Japan, “Electrical Equipment Diagnosis Technology Revised Edition”

[Problems related to power outage work]
In the conventional partial discharge measuring apparatus described with reference to FIG. 16 described above, the electric circuit connected to the mold transformer to be measured is temporarily interrupted, and one end of the detector 10, the electro-optical converter 20, and the optical cable 30 is transformed. After connecting to the tap terminals 5 and 5a of the transformer, the transformer was charged again, and the partial discharge was measured by the display unit 43 via the other end of the optical cable 30, the photoelectric converter 41, and the main amplifier 42. Then, the electric circuit connected to the transformer is blacked out again, and the work of removing one end of the detector 10, the electro-optical converter 20, and the optical cable 30 and charging the transformer again becomes necessary. That is, in this case, two power outages are involved in performing partial discharge measurement of the transformer in use. Further, the operation of connecting or removing one end of the detector 10, the electro-optical converter 20, and the optical cable 30 to or from the tap terminals 5, 5a of the transformer is performed by the tap terminal 5, which becomes a high potential during charging. Since the work is in contact with 5a, it is necessary to carry out work with sufficient measures to prevent electric shock.

  As described above, in the conventional partial discharge measuring apparatus described with reference to FIG. 16, in order to perform partial discharge measurement of a molded transformer that is installed in the field and has started operation, two power outages are required. However, regarding this point, the above-mentioned Patent Document 3 and Patent Document 4 disclose improvement proposals for improving workability in partial discharge measurement.

  That is, in the configuration described in Patent Document 3, the connection between the detector formed of a through-type current transformer through which the tap connection conductor passes and the electro-optical converter in which the amplifier is housed on the input side is fitted by a connector. By adopting the combination method, a detector can be laid in advance on the tap terminal on the high potential side, which eliminates the need for attaching / detaching the tap connection conductor between the tap terminals, and preparation necessary for partial discharge measurement. Work time can be reduced. Further, when performing partial discharge measurement with the configuration described in Patent Document 3, although not described in Patent Document 3, the mold transformer to be measured is kept in an operating state, and an insulation provided with a gripping mechanism is provided. Connect the electrical-to-optical converter to a detector charged to a high potential using a rod, etc., and measure the partial discharge. After the measurement, detect the electrical-to-optical converter using the insulating rod. An implementation method of removing from the vessel is conceivable, and according to such an implementation method, partial discharge measurement can be performed without a power failure operation.

  In the configuration described in Patent Document 4, as a partial discharge sensor, an amplifier, an electro-optical converter, and a battery power source are connected in advance in a state where the amplifier is connected to a detector composed of a through-type alternating current through which a tap connection conductor passes. By laying on the high potential side tap terminal side and supplying the power for charging the battery power by the transmission means via an insulating medium such as optical transmission on the high potential side, the amplifier and the electro-optical conversion The battery power supply for supplying power to the battery can be charged without power failure.

  Note that the configuration described in Patent Document 4 is not a configuration in which the connection between the detector and the amplifier can be freely attached and detached as a fitting method using a connector, so when performing partial discharge measurement, between the tap terminals. However, the connector connecting method described in Patent Document 3 is applied as the connection structure between the detector and the amplifier in the structure described in Patent Document 4. For example, a detector can be installed in advance on the tap terminal on the high potential side, eliminating the need for removing and attaching the tap connection conductor between the tap terminals, reducing the time required for preparatory work required for partial discharge measurement. In addition, if an insulation rod or the like is used to connect to and remove from a detector such as an amplifier, partial discharge measurement can be performed without power outage. It is considered to be able to also.

  As described above, if the configurations disclosed in Patent Document 3 and Patent Document 4 described above are used, partial discharge measurement and charging to the battery power source can be performed without a power outage operation. Has the following problems.

  First, in the configuration described in Patent Document 3, when a mold transformer is left in an operating state and an electro-optical converter is connected to a detector charged to a high potential by an insulating rod or the like, the ground potential side Since the electrical-to-optical converter is suddenly applied to the high potential side, a spark discharge is generated at the mating connector portion, thereby causing the amplification unit housed on the input side inside the electrical-to-optical converter. There is a possibility that the electronic circuit built into the will be damaged.

Further, the configuration described in Patent Document 4 is a method of supplying power for charging the battery power supply in a state of being insulated between the high potential side and the ground potential side. For example, an optical device capable of optically transmitting energy corresponding to a power of about several hundred mW is required, which increases the cost of the optical device. In the case of the configuration in which the power generation is performed on the high potential side, the power generation mechanism on the high potential side is complicated, so that the cost increases and the reliability as the partial discharge measuring device is low.

[Problems related to detection sensitivity]
Next, as described above, the partial discharge measuring device disclosed in Patent Document 8 is configured to capture high-frequency electromagnetic waves caused by partial discharge generated in the high-voltage winding of the transformer by using a loop antenna that is brought close to it. Since the configuration of the partial discharge measuring device is not a configuration in which a cable is connected between the high potential side and the ground potential side, the measurement of partial discharge as in the conventional partial discharge measuring device described with reference to FIG. Therefore, there is no problem that power outage work is necessary.

  Further, as described above, the partial discharge measuring device disclosed in Patent Document 8 has a partial discharge by a configuration in which a loop antenna is brought close to a neutral point or a configuration in which an electric field component is canceled by a differential circuit. When capturing high-frequency electromagnetic waves from the loop antenna with a loop antenna, it is designed not to be affected by the strong electric field generated at the end of the winding. It is thought to contribute to reducing the influence of the electric field component.

  However, the partial discharge measuring device disclosed in Patent Document 8 is a loop antenna in which a high-frequency electromagnetic wave emitted from a winding conductor is transmitted as a current that flows when a partial discharge occurs in a high-voltage winding. Therefore, even if the signal processing by the differential circuit as described above is performed, the ambient noise is not weakened because the intensity of the captured electromagnetic wave is weak and the electromagnetic wave detection output from the loop antenna is small. When the level is high, it is difficult to perform partial discharge measurement with sufficiently high detection sensitivity to withstand the influence of noise.

[Problems related to detection sensitivity calibration]
Next, the partial discharge measuring device disclosed in the prior application (Japanese Patent Application No. 2006-263668) has non-contact detection means shown in Patent Document 8, and in Patent Document 8, radiation is caused by the structure of the device under measurement. Therefore, the partial discharge signal, which is a weak signal, is locally concentrated using a current transformer that can selectively extract the high-frequency component of the partial discharge in Patent Document 1, and the partial discharge signal is transmitted via a transmission antenna. This has the advantage that detection sensitivity can be improved. This method ensures electrical insulation between the detection unit placed on the high potential side of the electrical equipment and the reception unit placed on the ground potential side, and means other than optical fiber (optical cable) is used for signal transmission. Low discharge, high reliability, high detection sensitivity, no need for a drive power source in the detection unit permanently installed on the high potential side, and a partial discharge measurement device that does not require a power failure on the high piezoelectric path for measurement Can provide.

  However, as disclosed in the prior application (Japanese Patent Application No. 2006-263668), the detection sensitivity is calibrated in a partial discharge measuring apparatus having a configuration in which a detection unit is provided on the high potential side and a reception unit is provided on the ground potential side. In order to introduce a calibration pulse signal (simulated partial discharge signal) for calibration to the detection unit on the high voltage side without causing a power failure in the high piezoelectric path, a calibration pulse signal is injected from the ground potential side. It is necessary to propagate the calibration pulse signal through the transmission line to the detection unit on the high voltage side. In addition, since only passive signal conversion is possible on the high-piezoelectric path side of the transmission path, for example, even if a method of transmitting a calibration pulse signal from the ground potential side to the high-voltage side by light is applied, the detection unit performs partial discharge. In the case of a configuration for electrical detection, it is impossible to calibrate the detection sensitivity because the calibration pulse signal cannot be converted from an optical signal to an electrical signal by passive signal conversion.

As a method of injecting an electric calibration pulse signal from the ground side, there is an injection method through capacitive coupling, which is often performed in a partial discharge measuring device of a power cable. This is a method used when a foil-like electrode attached to an insulating layer on the shield sheath of a cable is used as a detection end of partial discharge. A foil-like injection configured to have electrostatic coupling to the shield sheath. This is a method of injecting a calibration pulse signal by attaching the end to an insulating layer on the shield outer sheath of the cable. In the case of such an injection method through capacitive coupling, the physical phenomenon in the propagation of the calibration pulse signal is a pulsed electric field. This is a form corresponding to the detection of the partial discharge by an electric field, so that the propagation property of the calibration pulse signal from the injection end to the detection end is good and stable calibration can be performed.

  FIG. 21 is a diagram schematically illustrating an example of a method of injecting a calibration pulse signal from the ground side to the main circuit conductor side through capacitive coupling in the partial discharge measuring apparatus. It is a figure shown in principle. In the calibration circuit shown in FIG. 21A, on the ground side, a calibration pulse electric field transmission electrode ED1 for applying a calibration pulse electric field is connected to a pulse power source. On the main circuit conductor side, a calibration pulse electric field receiving electrode ED2 for receiving a calibration pulse electric field is provided, and a capacitance Cc is formed between the calibration pulse electric field transmission electrode ED1 on the ground side. Further, a partial discharge detection electrode ED3 connected to the measurement unit is provided, and a capacitance Cd is formed between the main circuit conductor. The calibration pulse current flowing to the main circuit conductor side via the capacitance Cc is shunted into an impedance Ze that passes through the main circuit conductor detector and an impedance Zf that passes through other than the main circuit conductor detector.

  An equivalent circuit of the calibration circuit of FIG. 21A is as shown in FIG. In FIG. 21B, the measurement impedance Z0 on the measurement unit side is considered to be substantially constant, and the parallel combined impedance (Ze // Zf) of the impedances Ze and Zf in the main circuit conductor (Ze / Zf) / ( When Ze + Zf) is sufficiently smaller than the impedances Z (Cc) and Z (Cd) of the capacitances Cc and Cd, the detection voltage Vd at the partial discharge detection electrode ED3 is approximately expressed by the following equation (1). It is represented by

Vd∝V × (Ze // Zf) / Z (Cc) (1)
Here, both of the electrostatic capacitances Cc and Cd are determined only by the structure based on the shape of the electrode and the attachment position.

For this reason, once the electrode is attached, Z (Cc) in the above equation (1) is constant, and stable calibration can be performed by the calibration pulse signal from the pulse power supply.
On the other hand, in the partial discharge measuring device disclosed in the prior application (Japanese Patent Application No. 2006-263668), in which a pair of transmission antennas and reception antennas are opposed to each other and a partial discharge detection signal is transmitted by coupling of magnetic fields, The excitation of the antenna is caused by a partial discharge current flowing through the main circuit (electric circuit conductor) of the device under test. For this reason, when the potential difference that appears on the circuit due to the electric field generated by the electrostatic coupling is used as the calibration pulse signal, it is necessary to switch from the potential difference to the current. In the case of the main circuit, this potential difference is converted to the current. Since conversion depends on the impedance of the main circuit, the efficiency of conversion depends on the individual structure of the main circuit.

  In the calibration circuit of FIG. 21, the calibration pulse current that flows to the main circuit (electric circuit conductor) side via the capacitance Cc is the impedance Ze that passes through the detection unit of the main circuit and the impedance Zf that passes through other than the detection unit of the main circuit. Therefore, the ratio of the current Ie passing through the detection unit to the total current I of the calibration pulse current flowing on the main circuit side is expressed by the following equation (2).

Ie / I = Zf / (Ze + Zf) (2)
Therefore, the calibration pulse current Ie passing through the detection unit is strongly influenced by the part passing through other than the detection unit.

  When the measurement impedance Z0 on the measurement unit side is sufficiently large with respect to the parallel synthetic impedance (Ze // Zf) of the main circuit, the total current I is as follows with respect to the voltage V applied to the calibration pulse electric field transmission electrode ED1 ( 3) There is a relationship of the formula.

I = V / (Z (Cc) + (Ze // Zf)) (3)
Next, Patent Document 5 discloses a method of injecting a calibration pulse signal without causing a power failure in a high piezoelectric path, and a simulated pulse current that simulates a partial discharge current as a calibration pulse signal is used as a dedicated high-frequency current transformer, Alternatively, it is injected into the secondary winding of an instrument current transformer laid on the electric circuit, and the simulated pulse is transferred from the secondary winding at the ground side potential to the primary high-voltage circuit via the magnetic coupling of the current transformer. A calibration method of inducing current is disclosed. When the configuration of the calibration method according to Patent Document 5 is applied to the detection sensitivity calibration method in the partial discharge measuring apparatus according to the prior application (Japanese Patent Application No. 2006-263668), there are the following two problems.

(A) First problem:
The first problem is that the electrical propagation between the current transformer for injecting the calibration pulse signal and the device under measurement whose partial discharge is to be measured is low. Although the simulated pulse current injected through the current transformer propagates as current on the main circuit, it is shunted throughout the main circuit (high piezoelectric path), so the component ratio shunted to equipment that requires calibration is reduced. And the component ratio changes with the impedance with respect to the said electric current of the other apparatus attached to the main circuit (high piezoelectric path). And since the relationship between the current flowing in the main circuit portion (electrical conductor portion) provided with the detecting portion and the current flowing in the other portion has the relationship shown in the above equation (2), it is connected to the main circuit. It is greatly influenced by conditions other than the device under test. It is important to solve this problem and to flow a simulated pulse current as a calibration pulse signal stably and exclusively through the main circuit part (electric circuit conductor part) provided with the detection part.

(B) Second problem:
The second problem is related to a current transformer for injecting a calibration pulse signal.
(A) First, when using a current transformer for an instrument laid in an electric circuit as a current transformer for injecting a calibration pulse signal, the frequency characteristic in the magnetic circuit of the current transformer for the instrument is a calibration pulse signal, That is, since the frequency band of the simulated pulse current that simulates the partial discharge current is much lower, the problem is that the simulated pulse current cannot be injected with a sufficient S / N ratio.

  That is, since the waveform of the partial discharge current has a rise time of about 10 ns and a fall time of about 100 ns, the frequency spectrum of the partial discharge current is proportional to (1 / f) n from DC to several MHz. And then decrease. Here, the value of n is 1-2. On the other hand, since the current transformer for an instrument is manufactured corresponding to 50 to 60 Hz which is the main circuit frequency of the electric circuit, the energy medium of the primary current and the secondary current in the instrument current transformer The magnetic material for forming the magnetic field produces an effective magnetic flux in a magnetic field up to several kHz, but is effective for a magnetic field with a frequency higher than that due to a decrease in permeability and an increase in eddy current. No more magnetic flux. For this reason, the frequency characteristics in the magnetic circuit of the current transformer for an instrument are much lower than the frequency band of the simulated pulse current that simulates the partial discharge current having the above-described high-speed rising characteristics, even if the simulated pulse current is reduced to some extent. Even if it can be injected, the S / N ratio is insufficient.

    (B) On the other hand, when a dedicated high-frequency current transformer is used as the current transformer for injecting the calibration pulse signal, there is a problem of low saturation magnetic flux peculiar to the magnetic circuit corresponding to the high frequency, and the main current flowing through the main circuit When the current at the circuit frequency is large, it becomes impossible to inject a simulated pulse current due to magnetic saturation. To avoid this magnetic saturation, a large-sized high-frequency current transformer is necessary.

That is, the problem of the above item (a) due to the fact that the frequency characteristics of the magnetic circuit when using a current transformer for an instrument is much lower than the frequency band of the simulated pulse current is that the primary current and the secondary current are high frequency. This can be solved by selecting a magnetic material and structure capable of mediating electric current, but this requires a dedicated high-frequency current transformer. Ferrite and the like are known as magnetic cores of high-frequency current transformers that can pass high-frequency magnetic flux, but because the saturation flux density is low, magnetic saturation tends to occur at low frequencies, so it flows to the main circuit When the current of the main circuit frequency (for example, 50 to 60 Hz) is large, the simulated pulse current cannot be injected due to magnetic saturation. In order to avoid the magnetic saturation and enable the injection of the simulated pulse current even when the current of the main circuit is large, it is conceivable to increase the core cross-sectional area. This increases the manufacturing cost and increases the installation space.

[Object of the present invention]
The present invention has been made in view of the above circumstances, and does not require a driving power source in the detection section on the circuit conductor side, is low in cost, has high reliability, and is accompanied by a power outage of the circuit conductor in measurement. Partial discharge measurement device capable of performing partial discharge measurement with high detection sensitivity, and capable of quantitatively and reliably performing calibration of detection sensitivity without causing a power failure of the circuit conductor during calibration. An object of the present invention is to provide a calibration method for a measuring apparatus and a partial discharge measurement method.

  According to the present invention, there is provided a partial discharge measuring device for measuring a partial discharge generated inside an electric device, with a conductor of the electric device and / or an electric circuit conductor made of an external conductor connected to the electric device. Among them, a ring-shaped core made of a magnetic material that circulates the circuit conductor part through which the partial discharge current generated by the partial discharge flows, a secondary winding wound around the ring-shaped core, and a circuit conductor side composed of an air-core coil Two or more circuit conductor parts that are capacitively coupled to the circuit conductor side device part formed by forming a series circuit of the secondary winding and the circuit conductor side antenna. The first circuit conductor side device section provided at one of them is used as a simulated partial discharge signal receiving section, and a simulated partial discharge signal simulating partial discharge is received from the outside via the circuit conductor side antenna. In addition, the second electric circuit conductor side device provided in another place is used as the partial discharge detection unit, and the partial electric discharge detection signal is transmitted to the outside via the electric circuit conductor side antenna. The detection sensitivity when the portion is a partial discharge detection portion can be calibrated (invention of claim 1).

  According to the first aspect of the present invention, in the second circuit conductor side device section serving as the partial discharge detection section, the ring-shaped core and the secondary winding detect the partial discharge current flowing through the circuit conductor section. It functions as a current transformer, and the electric current conductor side antenna consisting of an air-core coil is excited by the partial discharge current detected by this through-type current transformer. A magnetic field as a partial discharge detection signal can be emitted.

  According to the first aspect of the present invention, the first electric conductor-side device unit serving as a simulated partial discharge signal receiving unit for a device under test having an electric conductor at the main circuit potential at which partial discharge is to be measured. By injecting a simulated partial discharge signal from the outside into the circuit conductor part on the calibration signal injection side via the antenna on the circuit conductor side, the circuit conductor is capacitively coupled to the circuit conductor part on the calibration signal injection side. The simulated partial discharge signal is propagated to the circuit conductor on the calibrated side, and the simulated partial discharge signal is received from the second circuit conductor side device provided on the circuit conductor on the calibrated side via the circuit conductor side antenna. It is possible to calibrate the detection sensitivity when the partial discharge detection signal is transmitted to the outside and the second circuit conductor side device unit is used as the partial discharge detection unit. Without accompanying, partial release It is possible to calibrate the sensitivity of the measuring device.

  According to the first aspect of the present invention, a ring-shaped core made of a magnetic material that circulates around the electric circuit conductor, a secondary winding wound around the ring-shaped core, and an electric conductor-side antenna comprising an air-core coil Since the electric circuit conductor side device unit composed of is bi-directional, it is shared by the same configuration both when used as a simulated partial discharge signal receiving unit and when used as a partial discharge detection unit Therefore, there is no need to change the configuration of the circuit conductor side device section provided in the circuit conductor section of the main circuit potential, and thereby partial discharge without power failure of the circuit conductor of the device under test. It is possible to calibrate the detection sensitivity of the measuring device.

  According to the first aspect of the present invention, the electric circuit conductor side device section is a passive circuit including a ring-shaped core made of a magnetic material, a secondary winding wound around the ring-shaped core, and an antenna made of an air-core coil. Since it is composed only of parts and does not include an amplifier or an electro-optical converter, it does not require a driving power supply, and therefore it is not necessary to supply power to the electric conductor. Furthermore, since the constituent materials of these passive circuit components are not easily deteriorated, the reliability of the device is not lowered even if the circuit conductor side device unit is always connected to the circuit conductor side.

  According to the first aspect of the present invention, in the first circuit conductor device unit serving as the simulated partial discharge signal receiving unit, the through-type is generated by the induced voltage generated in the circuit conductor side antenna that has received the simulated partial discharge signal from the outside. A current as a simulated partial discharge signal is induced in the circuit conductor portion on the calibration signal injection side via the current transformer. Then, the calibration signal injection-side circuit conductor part provided with the first circuit-conductor-side device part and the calibration-side circuit conductor part provided with the second circuit-conductor-side device part serving as the partial discharge detection part are static. Due to the capacitive coupling, the current of the simulated partial discharge signal having a high-speed rising characteristic induced in the circuit conductor part on the calibration signal injection side is passed through a sufficiently low impedance to the circuit conductor on the calibration target side. Flow into the department. As a result, the simulated partial discharge signal can be efficiently transmitted to the circuit conductor on the calibrated side, so that the simulated portion is externally connected to the antenna on the circuit conductor side of the first circuit conductor device serving as the simulated partial discharge signal receiving unit. The power of the signal transmission source that supplies the discharge signal can be reduced. Further, since it is possible to inject a simulated partial discharge signal in a concentrated manner on the circuit conductor portion on the calibrated side, calibration with respect to the magnitude of the partial discharge to be measured can be performed with high accuracy.

  Next, in the partial discharge measuring apparatus according to claim 1, a grounding side antenna including an air-core coil disposed to be spaced apart from the electric path conductor side antenna of the first electric path conductor side device unit, A first ground side serving as a simulated partial discharge signal transmitting unit for transmitting a simulated partial discharge signal via the ground side antenna, comprising a simulated signal generating unit for supplying a pulse current as a simulated partial discharge signal to the ground side antenna A grounding side antenna comprising an air-core coil provided on the grounding side and spaced apart from the electrical circuit conductor side antenna of the second electrical path conductor side device part, and the grounding side antenna An amplification display unit that amplifies and displays a signal from the first side, and a second ground side device unit that serves as a partial discharge receiving unit that receives a partial discharge detection signal via the ground side antenna is provided on the ground side. , The detection sensitivity is calibrated when the first and second grounding side device units are the simulated partial discharge signal transmission unit and the partial discharge reception unit, respectively, and the second circuit conductor side device unit is the partial discharge detection unit. It is preferable to be able to do this (invention of claim 2).

  According to the second aspect of the present invention, a pulse current as a simulated partial discharge signal supplied from the simulated signal generation unit in the first ground side apparatus unit which is a simulated partial discharge signal transmission unit provided on the ground side is received. The grounded antenna radiates a magnetic field as a simulated partial discharge signal, and an induced voltage is generated in the circuit conductor side antenna of the first circuit conductor side device, and this induced voltage penetrates the ring-shaped core of the feedthrough current transformer. A current is induced in the circuit conductor portion on the calibration signal injection side. The pulse current having a fast rise characteristic induced in the circuit conductor part on the calibration signal injection side is capacitively coupled to the circuit conductor part on the calibration signal injection side in the circuit conductor. In addition, the electric current flows mainly through a sufficiently low impedance due to capacitance, and the second electric circuit conductor side device provided in the electric circuit conductor on the calibrated side detects the pulse current as a partial discharge detection unit. In the second circuit conductor side device unit, as described above, the ring-shaped core and the secondary winding function as a through-type current transformer that detects a partial discharge current flowing through the circuit conductor unit on the calibration target side, The electric circuit conductor side antenna is excited by the partial discharge current detected by this through-type current transformer, and a magnetic field as a partial discharge detection signal is radiated from the second electric circuit conductor side device to the outside via the electric circuit conductor side antenna. The Then, the second ground side device unit receives the magnetic field as a partial discharge detection signal as a partial discharge receiving unit, a voltage is induced in the ground side antenna, and the voltage as the induced partial discharge reception signal is amplified and displayed. Amplified and displayed on the screen.

  In the invention of claim 2, as described above, the simulation is performed from the ground-side antenna of the first ground-side device unit, which is a simulated partial discharge signal transmission unit, toward the circuit-conductor-side antenna of the first circuit conductor-side device unit. By transmitting the partial discharge signal as a magnetic field, it is possible to calibrate the detection sensitivity of the partial discharge measuring device without causing a power failure of the circuit conductor of the device under measurement.

  In the second aspect of the invention, similar to the first aspect of the invention, the simulated partial discharge signal can be efficiently transmitted to the circuit conductor portion on the calibrated side. It is possible to reduce the power of the simulated signal generating unit in the simulated partial discharge signal transmitting unit that supplies the simulated partial discharge signal from the ground side to the circuit conductor side antenna of the one circuit conductor device unit. Further, since it is possible to inject a simulated partial discharge signal in a concentrated manner on the circuit conductor portion on the calibrated side, calibration with respect to the magnitude of the partial discharge to be measured can be performed with high accuracy.

  Further, in the partial discharge measuring apparatus according to claim 2, a set of configurations including the first circuit conductor side device unit and the ground side antenna of the first ground side device unit is arranged on the second circuit conductor side. The first and second ground-side device sections are respectively configured to be a simulated partial discharge signal transmitting section and a partial section by having the same configuration as a set of configurations including the device section and the ground-side antenna of the second ground-side apparatus section. In the state where the discharge receiving unit is used, calibration of the detection sensitivity when the second circuit conductor side device unit is used as the partial discharge detection unit can be performed, and the simulation signal generating unit and the first In the state where the amplification display unit in the two ground side device units is recombined with each other, and the first and second ground side device units are used as the partial discharge receiving unit and the simulated partial discharge signal transmission unit, respectively, The side device is the partial discharge detector The calibration of detection sensitivity may be able to do when (the invention of claim 3).

  According to the third aspect of the present invention, the simulated signal generation unit and the amplification display are made between the ground side device units provided corresponding to the plurality of circuit conductor side device units respectively provided at a plurality of locations of the circuit conductor of the device under test. Since the detection sensitivities of the plurality of circuit conductor side device units (partial discharge detection units) can be calibrated only by recombining the units with each other, the efficiency of the calibration work is further improved.

  Further, in the partial discharge measuring device according to claim 3, when the electric device is provided with a three-phase circuit, the electric discharge conductor side device portion and a ground side antenna of the ground side device portion are provided. It is good to provide the structure of a set in each phase of a three-phase circuit (invention of Claim 4).

  According to the fourth aspect of the present invention, in the electrical equipment having a three-phase circuit, the circuit conductors of the respective phases are structurally and electrically adjacent to each other, and the high frequency corresponding to the fast rising characteristics of the simulated partial discharge signal Since the capacitive coupling between the circuit conductors of each phase in the region is large, the impedance from the circuit conductor part of the phase into which the simulated partial discharge signal is injected to the circuit conductor part of the other phase to be calibrated is The simulated partial discharge signal injected into one phase of the three-phase circuit is equivalent to the reciprocal of the above impedance ratio as the pulse current because the simulated partial discharge signal injected into one phase of the three-phase circuit is lower than the impedance to the electric conductor portion outside the device. Thus, the influence from devices and devices other than the electrical device, which is the device to be measured, can be reduced in calibration of detection sensitivity.

The partial discharge measuring apparatus according to any one of claims 1 to 4, wherein the electric circuit conductor side apparatus unit includes a ring-shaped core made of a magnetic body that circulates around the electric circuit conductor unit, and a coil wound around the ring-shaped core. A secondary winding to be rotated, a capacitor, and an electric conductor-side antenna composed of an air-core coil, and forming a series resonance circuit of the secondary winding, the capacitor, and the electric conductor-side antenna. (Invention of claim 5).

  According to the fifth aspect of the present invention, in the circuit conductor side device section serving as the partial discharge detection section, the through-type current transformer in which the ring-shaped core and the secondary winding detect the partial discharge current flowing through the circuit conductor section. The partial discharge current detected by this through-type current transformer excites a series resonant circuit of a secondary winding, a capacitor, and an antenna on the side of a circuit conductor consisting of a capacitor and an air-core coil. Thus, a strong magnetic field as a partial discharge detection signal can be radiated to the outside through the antenna on the electric conductor side. As a result, the spatial distance between the circuit-conductor-side antenna of the circuit-conductor-side device unit serving as the partial discharge detection unit and the external receiving means that receives the partial discharge detection signal is sufficient to ensure electrical insulation. In addition to the distance, it is possible to withstand the influence of ambient noise and perform partial discharge measurement with higher detection sensitivity.

  According to the invention of claim 5, in the circuit conductor device unit serving as the simulated partial discharge signal receiving unit, the induced voltage generated in the circuit conductor side antenna that has received the simulated partial discharge signal from the outside, Since a series resonant circuit consisting of a capacitor and the secondary winding of a feedthrough current transformer is excited, a large current is induced as a simulated partial discharge signal in the circuit conductor on the calibration signal injection side via the feedthrough current transformer. Is done. As a result, it is possible to further reduce the power of the signal transmission source that supplies the simulated partial discharge signal from the outside to the circuit conductor side antenna of the circuit conductor device unit serving as the simulated partial discharge signal receiving unit.

  Further, in the partial discharge measuring device according to claim 2, the second ground side that receives the partial discharge detection signal transmitted from the second circuit conductor side device unit serving as the partial discharge detection unit as a reception signal. A frequency-specific level measuring means capable of inputting the received signal to the amplification display unit of the apparatus unit and measuring the frequency-specific level of the received signal by changing the measurement frequency with a certain bandwidth; and a second electric circuit In the detection sensitivity calibration step of calibrating the detection sensitivity when the conductor side device unit is a partial discharge detection unit, the measurement output of the level measuring means for each frequency is input, and the simulated partial discharge signal is injected The signal level for each frequency and the background level for each frequency when the simulated partial discharge signal is not injected are read, the signal level is high, and the signal level and A frequency with a high S / N ratio, which is a ratio of the size to the ground level, is obtained as a tuning frequency, and an actual partial discharge is measured in a state where the second circuit conductor side device unit is a partial discharge detection unit. In the partial discharge measurement step, a signal processing means for providing the tuning frequency to the frequency level measuring means as a command value of the measurement frequency is provided, and the measurement frequency of the frequency level measuring means is actually set in the tuning frequency. It is preferable that the measurement of partial discharge can be performed.

  According to the sixth aspect of the present invention, the partial discharge measurement can be performed in synchronization with the resonance frequency due to the inductance of the electric circuit conductor such as the winding conductor and the connection conductor in the electrical equipment for which the partial discharge is to be measured. Thus, partial discharge measurement with a high S / N ratio can be performed.

Next, according to the present invention, a calibration method in a partial discharge measuring device for measuring partial discharge generated inside an electric device is performed by using a conductor included in the electric device and / or an external device connected to the electric device. A ring-shaped core made of a magnetic material that circulates the circuit conductor part through which the partial discharge current generated by the partial discharge among the circuit conductors made of a conductor, a secondary winding wound around the ring-shaped core, and an air core An electric circuit conductor side antenna comprising a coil, and an electric circuit conductor side device formed by forming a series circuit of the secondary winding and the electric circuit conductor side antenna is capacitively coupled in the electric circuit conductor. The first electric circuit conductor side device provided at one location is used as a simulated partial discharge signal receiving unit, and the first electric circuit conductor side device is connected to the first electric circuit conductor side antenna via the electric circuit conductor antenna. Outside And receiving a simulated partial discharge signal simulating the partial discharge, and using the second electric conductor-side device section provided at another location as the partial discharge detector, and the electric conductor-side antenna of the second electric conductor-side apparatus portion. By transmitting the partial discharge detection signal to the outside, the detection sensitivity is calibrated when the second circuit conductor side device unit is the partial discharge detection unit (invention of claim 7).

  According to the seventh aspect of the present invention, similar to the first aspect of the present invention, a simulated partial discharge signal receiving unit is provided for a device under test having a circuit conductor at a main circuit potential at which partial discharge is to be measured. Injecting a simulated partial discharge signal from the outside into the circuit conductor part on the calibration signal injection side via the circuit conductor side antenna of the first circuit conductor side device section, and the circuit conductor part on the calibration signal injection side in the circuit conductor The simulated partial discharge signal is propagated to the circuit conductor on the calibration target side that is capacitively coupled, and the circuit conductor antenna is connected from the second circuit conductor side device provided on the circuit conductor on the calibration target side. The partial discharge detection signal corresponding to the simulated partial discharge signal can be transmitted to the outside, and the detection sensitivity can be calibrated when the second circuit conductor side device unit is the partial discharge detection unit. Of the circuit conductor of the device under test Without electricity, it is possible to calibrate the sensitivity of the partial discharge measuring device.

  According to the seventh aspect of the present invention, the simulated partial discharge signal can be efficiently transmitted to the circuit conductor portion on the calibrated side in the same manner as the first aspect of the invention. It is possible to reduce the power of the signal transmission source that supplies the simulated partial discharge signal from the outside to the antenna on the circuit conductor side of the first circuit conductor device unit, and the simulated part is concentrated on the circuit conductor unit on the calibration target side. Since it is possible to inject a discharge signal, calibration for the magnitude of the partial discharge to be measured can be performed with high accuracy.

  8. The method for calibrating a partial discharge measuring device according to claim 7, wherein the grounding side is formed of an air-core coil disposed at a spatial distance so as to face the electric conductor-side antenna of the first electric conductor-side device. An antenna and a simulation signal generation unit that supplies a pulse current as a simulation partial discharge signal to the ground side antenna, and serves as a first simulation partial discharge signal transmission unit that transmits the simulation partial discharge signal via the ground side antenna. A grounding side antenna unit is provided on the grounding side, and the grounding side antenna is formed of an air-core coil arranged at a spatial distance so as to face the circuit conductor side antenna of the second circuit conductor side unit, and the grounding And an amplification display unit for amplifying and displaying a signal from the side antenna, and a second ground side device unit serving as a partial discharge receiving unit for receiving the partial discharge detection signal via the ground side antenna is provided on the ground side. The second And calibration of detection sensitivity when the second circuit side device unit is a partial discharge detection unit with the second ground side device unit being a simulated partial discharge signal transmission unit and a partial discharge reception unit, respectively. (Invention of claim 8) is preferable.

  According to the eighth aspect of the present invention, similar to the second aspect of the present invention, from the ground side antenna of the first ground side device unit which is a simulated partial discharge signal transmission unit to the circuit conductor of the first circuit side device. By transmitting the simulated partial discharge signal as a magnetic field toward the side antenna, it is possible to calibrate the detection sensitivity of the partial discharge measuring device without causing a power failure of the circuit conductor of the device under measurement. Furthermore, since the simulated partial discharge signal can be efficiently transmitted to the circuit conductor portion on the calibrated side, the simulated portion from the ground side is connected to the circuit conductor side antenna of the first circuit conductor device portion serving as the simulated partial discharge signal receiving portion. It is possible to reduce the power of the simulation signal generation unit in the simulation partial discharge signal transmission unit that supplies the discharge signal. Further, since it is possible to inject a simulated partial discharge signal in a concentrated manner on the circuit conductor portion on the calibrated side, calibration with respect to the magnitude of the partial discharge to be measured can be performed with high accuracy.

Further, in the method for calibrating a partial discharge measuring device according to claim 8, a set of configurations including a first electric conductor-side device unit and a ground-side antenna of the first ground-side device unit has a second configuration. The same configuration as one set of the conductor-side device unit and the ground-side antenna of the second ground-side device unit is set, and the first and second ground-side device units are each a simulated partial discharge signal transmitting unit and In the state where the partial discharge receiving unit is used, calibration of the detection sensitivity when the second circuit conductor side device unit is used as the partial discharge detection unit is performed, and the simulation signal generation unit and the second signal generation unit in the first ground side device unit are calibrated. In the state where the amplification display unit in the ground side device unit is recombined with the first and second ground side device units as the partial discharge receiving unit and the simulated partial discharge signal transmission unit, respectively, Detection when the part is a partial discharge detector Better to perform calibration of the degree (the invention of claim 9).

  According to the ninth aspect of the invention, as in the third aspect of the invention, the grounding side device provided corresponding to the plurality of circuit conductor side device portions respectively provided at the plurality of locations of the circuit conductor of the device under test. By simply recombining the simulated signal generation unit and the amplification display unit with each other, the detection sensitivity of multiple circuit conductor side device units (partial discharge detection units) can be calibrated, improving the efficiency of calibration work. To do.

  Further, in the method for calibrating a partial discharge measuring device according to claim 9, wherein the electric device includes a three-phase circuit, and includes an electric conductor side device unit and a ground side antenna of the ground side device unit. A set of configurations is provided for each phase of the three-phase circuit, and a simulation signal generator is connected to one of the three-phase configurations to connect the ground side device unit of this phase to the simulated partial discharge signal. It is preferable to calibrate the detection sensitivity when the generation unit is a partial discharge detection unit of the circuit conductor side device unit of another phase (invention of claim 10).

  According to the tenth aspect of the present invention, similar to the fourth aspect of the invention, in the electrical equipment having the three-phase circuit, the circuit conductors of each phase are structurally and electrically adjacent to each other, and the simulated partial discharge Since the capacitive coupling between the circuit conductors of each phase in the high-frequency region corresponding to the fast rise characteristics of the signal is large, the other phase to be calibrated from the circuit conductor part of the phase into which the simulated partial discharge signal is injected Since the impedance to the circuit conductor part of the three-phase circuit is lower than the impedance to the circuit conductor part outside the electrical device, the simulated partial discharge signal injected into one phase of the three-phase circuit is the pulse current of the other-phase circuit conductor part. Flows at a large ratio corresponding to the reciprocal of the impedance ratio described above, and this reduces the influence of devices other than the electrical device, which is the device under test, in the detection sensitivity calibration. Can Kusuru.

  The method of calibrating a partial discharge measuring device according to any one of claims 7 to 10, wherein the circuit conductor side device section includes a ring-shaped core made of a magnetic body that circulates around the circuit conductor section, and the ring. A secondary winding wound around the core, a capacitor, and an electric conductor-side antenna composed of an air-core coil, and forming a series resonance circuit of the secondary winding, the capacitor, and the electric conductor-side antenna It is good to be made (Invention of Claim 11).

  According to the eleventh aspect of the present invention, as in the fifth aspect of the present invention, in the circuit conductor side device section serving as the partial discharge detecting section, the ring-shaped core and the secondary winding flow through the circuit conductor section. A series resonance circuit that functions as a feedthrough current transformer that detects the discharge current, and that includes a secondary winding, a capacitor, and an antenna on the side of the electric conductor formed of an air-core coil by the partial discharge current detected by the feedthrough current transformer Therefore, a strong magnetic field as a partial discharge detection signal can be radiated from the partial discharge detection unit to the outside via the circuit conductor antenna.

  According to the invention of claim 11, as in the invention of claim 5, in the circuit conductor device part serving as the simulated partial discharge signal receiving unit, the circuit conductor side antenna receiving the simulated partial discharge signal from the outside is used. The induced voltage excites a series resonant circuit composed of the antenna on the circuit conductor side, the capacitor, and the secondary winding of the feedthrough current transformer, so that the circuit conductor section on the calibration signal injection side through the feedthrough current transformer A large current is induced as a simulated partial discharge signal. As a result, it is possible to further reduce the power of the signal transmission source that supplies the simulated partial discharge signal from the outside to the circuit conductor side antenna of the circuit conductor device unit serving as the simulated partial discharge signal receiving unit.

  In addition, a partial discharge measuring method for measuring a partial discharge generated inside an electric device using the partial discharge measuring device according to claim 2 is provided from a second circuit conductor side device section serving as a partial discharge detection section. The amplification display unit of the second ground-side device unit that receives the transmitted partial discharge detection signal as a reception signal can change the measurement frequency with a certain bandwidth to measure the level of the reception signal for each frequency. Detection sensitivity calibration for providing frequency-specific level measurement means, inputting the received signal to the frequency-specific level measurement means, and calibrating detection sensitivity when the second circuit conductor side device unit is a partial discharge detection unit In the process, the signal level for each frequency when the simulated partial discharge signal is injected, and the background level for each frequency when the simulated partial discharge signal is not injected. Each reading is performed to obtain a frequency having a high signal level and a high S / N ratio, which is a ratio between the signal level and the background level, as a tuning frequency, and then the second electric circuit conductor side device section is partially discharged. In the actual partial discharge measurement step of measuring an actual partial discharge in a state of being a detection unit, the partial discharge measurement is performed by setting the measurement frequency of the level measuring means for each frequency to the tuning frequency. invention).

  According to the invention of the twelfth aspect, in the same manner as the invention of the sixth aspect, the part is tuned to the resonance frequency due to the inductance of an electric circuit conductor such as a winding conductor or a connection conductor in an electric device whose partial discharge is to be measured. Discharge measurement can be performed, and partial discharge measurement with high sensitivity and high S / N ratio can be performed.

  According to the present invention, partial discharge measurement can be performed with high detection sensitivity without causing a power failure of the electric conductor, and the detection sensitivity can be calibrated quantitatively and reliably.

Embodiments of the present invention will be described below with reference to the drawings.
Constituent elements that are the same as conventional ones are given the same reference numerals, and redundant descriptions are omitted. In addition, this invention is not limited to the following embodiment, In the range which does not change the summary, it can implement suitably.

[First Embodiment]
In the present embodiment, in particular, the partial discharge detector in the partial discharge measuring apparatus of the type that transmits the detection signal described in the prior application (Japanese Patent Application No. 2006-263668) as a magnetic field is used as a three-phase device for power. One set is provided for each phase. A partial discharge detector provided in one phase of each phase is used for injection of a calibration pulse signal that is a simulated partial discharge signal, and is detected in a partial discharge detector provided in another phase, thereby providing a detection phase. Calibrate the detection sensitivity of the device. In a three-phase device such as a three-phase transformer, which is a device under test, the main circuits (electric circuit conductors) of each phase are structurally and electrically adjacent to each other, and the main circuit portion into which the calibration pulse signal is injected (for example, The impedance up to the main circuit part (for example, the V-phase circuit conductor part) of the detection target to be calibrated as viewed from the U-phase circuit conductor part) is up to the main circuit part (circuit conductor part) outside the device under test. Usually it is lower than the impedance. As a result, the calibration pulse signal injected into one phase (for example, U phase) of the three-phase device causes the main circuit portion (electric circuit conductor portion) of the detection unit in the other phase (for example, V phase) as the pulse current to have the above impedance. Since it flows at a large ratio corresponding to the reciprocal of the ratio, it is possible to reduce the influence from devices and devices other than the device under measurement in calibration of detection sensitivity.

  FIG. 1 is a diagram showing a configuration example of the first embodiment of the present invention, and shows an example of the overall configuration when the present invention is applied to a three-phase transformer. FIG. 2 is a diagram showing a partial discharge detector and a simulated partial discharge signal transmitter that form a calibration pulse signal injection system in the partial discharge measuring apparatus according to the first embodiment of the present invention.

In this embodiment, among the phases of a three-phase device such as a power three-phase transformer that is a target of partial discharge measurement, the phase (for example, U phase) used for injection of the calibration pulse signal is shown in FIG. In the partial discharge measuring apparatus of the prior application (Japanese Patent Application No. 2006-263668), the partial discharge receiving unit 200 including the receiving antenna 201, the matching unit 202, the transmission cable 203, the preamplifier 204, the main amplifier 205, and the display unit 206, As shown in FIG. 2, a simulated partial discharge signal transmission unit 300 including a pulse power supply 305, a series capacitor 304, a transmission cable 303, a matching unit 302, and a transmission antenna 301 is replaced. On the other hand, in a phase other than the phase used for injection of the calibration pulse signal (for example, V phase and W phase), partial discharge receiving unit 200 shown in FIG. 19 is provided as it is.

  FIG. 1 shows the AA cross section of FIG. 15 as the structure of the transformer main body in the three-phase molded transformer, which is a device under test, and the high-voltage windings 1U, 1V, and 1W of the respective phases. Partial discharge detectors 100U, 100V, and 100W are provided as the circuit conductor side device units, and a simulated partial discharge signal transmission unit 300 is provided as a ground side device unit corresponding to the U-phase partial discharge detector unit 100U. A configuration is shown in which partial discharge receiving units 200a and 200b are provided as ground side device units corresponding to W phase partial discharge detection units 100V and 100W, respectively. Here, FIG. 1 shows the apparatus configuration in the process of calibrating the detection sensitivity on the V and W phase sides by the calibration signal injection from the U phase side in the calibration work process of the partial discharge measuring apparatus. The phases in which the partial discharge signal transmission unit 300 and the partial discharge reception unit 200 are provided are switched according to the progress of the calibration work process, as will be described later.

  In FIG. 1, the low-voltage windings and the main legs of the iron core that are disposed on the inner diameter side of the high-voltage windings 1U, 1V, 1W are not shown. In addition, arrows drawn between the opposing antennas in each phase (between U-phase antennas 101U and 301, between V-phase antennas 101V and 201, and between W-phase antennas 101W and 201) indicate the magnetic field of the calibration pulse signal. Indicates the transmission direction.

(Configuration and operation of calibration pulse signal injection system)
In the calibration pulse signal injection system including the simulated partial discharge signal transmission unit 300 (grounding side device unit) and the partial discharge detection unit 100 (electric circuit conductor side device unit) shown in FIG. 2, the pulse power source 305 is used as a calibration pulse signal. This is a power supply that can output a square-wave voltage signal with the same rise characteristics as the partial discharge to be measured. The rise time is several nanoseconds for partial discharges caused by defects in gases and solids and creeping surfaces of solids. Since it is several tens of nanoseconds, the rise characteristic conforms to this. The series capacitor 304 converts a voltage signal from the pulse power supply 305 into a charge signal as a signal form of the calibration pulse signal. Since the magnitude of the partial discharge is evaluated based on the amount of charge, the series capacitor 304 is inserted on the output side of the pulse power source 305 in order to correspond to the physical amount. A pulse current having a charge amount (Qa = Cb * Ec) determined by the output voltage (Ec) 305 and the capacitance (Cb) of the series capacitor 304 is output from the series capacitor 304. As described above, the pulse power supply 305 and the series capacitor 304 constitute a simulated signal generation unit that supplies a pulse current as a calibration pulse signal to the transmitting antenna 301 side. The waveform of the voltage signal output from the pulse power supply 305 may be a waveform other than the rectangular wave described above. For example, the waveform that rises in a short time and then attenuates more slowly than the rise and returns to the baseline. It may be.

Next, the calibration pulse signal (charge signal) from the series capacitor 304 becomes a pulse current and propagates through the transmission cable 303 and enters the matching unit 302. The matching unit 302 is provided to match the impedance between the transmission cable 303 and the subsequent transmission antenna 301 and to improve the radiation efficiency from the transmission antenna 301. The calibration pulse signal transmitted to the transmitting antenna 301 as a charge signal (pulse current) is radiated as a magnetic field from the transmitting antenna 301, and the antenna 10 of the partial discharge detection unit 100 (electrical conductor side device unit) provided oppositely.
1 is transmitted to the main circuit portion (electrical conductor portion) through the detector 110 including a capacitor and a current transformer. As described above, the partial discharge detection unit 100 (electrical conductor side device unit) in the calibration pulse signal injection system functions as a simulated partial discharge signal receiving unit that receives a simulated partial discharge signal transmitted from the ground side. .

(Compatibility of equipment between calibration signal injection phase and phase to be calibrated and calibration procedure)
(A) The components other than the pulse power supply 305 and the series capacitor 304 in the simulated partial discharge signal transmission unit 300 (ground side device unit) are completely the same as the components in the partial discharge receiver 200 (ground side device unit) shown in FIG. The same can be used. That is, since the transmission cable 303, the matching unit 302, and the transmission antenna 301 all have a bidirectional action, the transmission cable 203, the matching unit 202, and the reception antenna 201 in FIG. it can.

  Further, the antenna 101 of the facing partial discharge detector 100 (electrical conductor side device unit) is also bidirectional, and further, the tap connection conductor 7, the ring-shaped core 11, and the secondary winding 12. Similarly, the detector 110 (see FIG. 20) including the through-type current transformer made of the capacitor and the capacitor 113 has bidirectionality. As a result, the partial discharge detection unit 100 (electrical conductor side device unit) including the antenna 101 and the detector 110 in the main circuit portion (electric circuit conductor unit) transmits from the simulated partial discharge signal transmission unit 300 (ground side device unit). Even when it is used for receiving the calibration pulse signal (simulated partial discharge signal) and injecting it into the main circuit portion (electrical conductor portion), it detects the actual partial discharge and receives the partial discharge receiver 200 (grounding side device). Even if it is used for transmission to the main circuit part, it can be shared and functions can be exchanged with each other as it is, so the main circuit part (electric circuit conductor part) charged to a high voltage during calibration using the calibration pulse signal (simulated partial discharge signal) No need to touch).

  Accordingly, in FIG. 1, for example, a set of devices including a partial discharge detection unit 100U (electric circuit conductor side device unit) corresponding to the U phase and a transmission antenna 301 of the simulated partial discharge signal transmission unit 300 (ground side device unit). U-phase side in the configuration and one set of device configuration including a partial discharge detection unit 100V (electrical conductor side device unit) corresponding to the V phase and a reception antenna 201 of the partial discharge reception unit 200a (ground side device unit) The one set of device configuration and the one set of device configuration on the V-phase side can be made the same.

  (B) In the simulated partial discharge signal transmission unit 300 (grounding side device unit) corresponding to the U phase, the transmission antenna 301 and a portion other than the transmission antenna 301 (after the matching unit 302) (simulated signal generation unit) In the partial discharge receiving unit 200a (grounding side device unit) corresponding to the V phase, the receiving antenna 201 and the part other than the receiving antenna 201 (after the matching unit 202) (amplification display unit) can be classified. Be able to do that.

  Then, as shown in FIG. 1, in the state where the U-phase side and V-phase side ground side device sections are the simulated partial discharge signal transmission section 300 and the partial discharge reception section 200a, respectively, the V-phase side partial discharge detection section 100V. After calibrating the detection sensitivity of the (electrical conductor side device unit), the U phase side simulated partial discharge transmission unit 300 (grounding side device unit) other than the transmission antenna 301 (simulated signal generation unit) and the V phase The partial discharge receiving section 200a (grounding side apparatus section) on the side of the ground side apparatus section on the U-phase side and the V-phase side is partially discharged by recombining parts other than the receiving antenna 201 (amplification display section) with each other. With the receiving unit 200a and the simulated partial discharge signal transmission unit 300, the detection sensitivity of the U-phase side partial discharge detection unit 100U (electrical conductor side device unit) can be calibrated.

In the above description, the ground device unit, that is, the simulated partial discharge signal transmission unit and the partial discharge reception unit, is divided into an antenna and a portion other than the antenna as a method of dividing each device configuration. The present invention is not limited to the above-described configuration, and is configured to be divided into an antenna side portion composed of an antenna and a matching unit and a subsequent anti-antenna side portion, or an antenna composed of an antenna, a matching unit, and a transmission cable. A configuration in which a side portion and a subsequent anti-antenna side portion are applied is applied, and the anti-antenna side portion (simulated signal generating portion) in the U-phase side simulated partial discharge transmitting unit 300 and the V-phase side partial discharge receiving unit The part opposite to the antenna 200a (amplification display part) in 200a may be recombined.

  Here, it is preferable to apply a configuration that is easy to detach and attach and has a high connection reliability, such as a connector connection structure, to a portion that divides the device configuration in the ground side device unit. In this regard, in FIG. 1, between the transmission cable 303 and the series capacitor 304 in the simulated partial discharge transmitter 300 on the U phase side and between the transmission cable 203 and the preamplifier 204 in the partial discharge receiver 200a on the V phase side. In this example, the connector connection portions 311 and 211 are respectively connected.

Further, the above-described method of recombining the devices on the non-antenna side portion in the ground side device unit between the U phase side and the V phase side is the same between the U phase side and the W phase side.
(C) In the case of mutual recombination between the U-phase side and the V-phase side, the entire simulated partial discharge transmission unit 300 (grounding side device unit) including the U-side transmission antenna 301 and the V-phase side The entire partial discharge receiving unit 200a (grounding side device unit) including the receiving antenna 201 may be recombined with each other.

  (D) As shown in FIG. 1, partial discharge detectors 100U, 100V, and 100W are provided for all three phases, and a simulated partial discharge signal transmitter 300 is provided for one phase (the U phase in FIG. 1). The calibration procedure in the configuration in which the partial discharge receivers 200a and 200b are provided in two phases (V and W phases in FIG. 1) can be, for example, as follows.

(A) In the apparatus configuration shown in FIG. 1, calibration of detection sensitivity on the V and W phases is performed by calibration signal injection from the U phase.
(B) The simulated partial discharge signal transmission unit 300 provided in the U phase and the partial discharge reception unit 200a provided in the V phase are recombined with each other, and the detection on the U phase side is performed by injecting a calibration signal from the V phase side. Perform sensitivity calibration.

  (E) In FIG. 1, partial discharge detectors 100U, 100V, and 100W are provided for all three phases, a simulated partial discharge signal transmitter 300 is provided for one phase (the U phase in FIG. 1), and the other two phases Although the partial discharge receiving units 200a and 200b are provided in the respective phases (V and W phases in FIG. 1), the partial discharge receiving unit 200 is in one phase (in FIG. 1, either the V phase or the W phase). It is good also as a structure only provided. The calibration procedure in the latter configuration can be as follows, for example.

(A) In the apparatus configuration in which the partial discharge receiving unit 200 is provided only in the V phase in FIG. 1, the detection sensitivity calibration on the V phase side is performed by injecting the calibration signal from the U phase side.
(B) The partial discharge receiving unit 200 provided in the V phase is moved to the W phase, and detection sensitivity calibration on the W phase side is performed by injecting a calibration signal from the U phase side.

    (C) The simulated partial discharge signal transmitting unit 300 provided in the U phase and the partial discharge receiving unit 200 provided in the W phase are recombined with each other, and the U phase side is detected by injecting a calibration signal from the W phase side. Perform sensitivity calibration.

(Configuration example of antenna pair in partial discharge measuring device)
FIG. 3 shows the antenna pair in the partial discharge measuring device according to the first embodiment of the present invention, that is, the configuration of each antenna of the partial discharge detection unit (electrical conductor side device unit) and partial discharge reception unit (ground side device unit). FIG. 3A is a side view showing a state where the antennas of the partial discharge detector and the partial discharge receiver are opposed to each other, and FIG. 3B is a partial discharge receiver. It is a front view which shows the structure of the antenna of a part.

  The antenna 101 of the partial discharge detector 100 installed on the high piezoelectric path side (electrical conductor side) is covered with an insulating material 131, and a concave portion 132 is provided at the center of the insulating material 131. The antenna 201 of the partial discharge receiving unit 200 installed on the ground side is also covered with an insulating material 231, and a convex portion 232 is provided at the center of the insulating material 231. The antenna 201 is provided with an insulating handle 233 made of a long insulating material.

  When the antenna 201 of the partial discharge receiving unit 200 is brought close to the antenna 101 of the partial discharge detection unit 100 in order to perform partial discharge measurement, the antenna 201 is supported by the operator's hand through the insulating handle 233 and visually observed. By the work, the convex portion 232 of the insulating material 231 on the antenna 201 side corresponds to the concave portion 132 of the insulating material 131 on the antenna 101 side, and the antenna 101 side is brought close to the antenna 101 side. At this time, the insulation between the high-voltage path and the ground may be sufficiently insulative because the insulating material 131 on the antenna 101 side and the insulating material 231 on the antenna 201 side are configured in series. it can.

  Note that the antenna 301 of the simulated partial discharge signal transmission unit (ground side device unit) 300 described in FIG. 2 has the same configuration as the antenna 201 of the partial discharge reception unit (ground side device unit) 200 in FIG. It is possible to adopt a configuration in which an insulating handle (not shown) made of a long insulating material is attached. The operation of bringing the antenna 301 of the simulated partial discharge signal transmission unit 300 close to the antenna 101 of the partial discharge detection unit 100 in order to inject the calibration pulse signal is performed using the antenna 201 of the partial discharge reception unit 200 described with reference to FIG. This can be performed in the same manner as the operation of bringing the partial discharge detector 100 close to the antenna 101.

(Calibration pulse signal transmission path in the device under test)
FIG. 4 is a diagram showing an electric circuit serving as a transmission path of a calibration pulse signal (simulated partial discharge signal) in a three-phase transformer, and calibration when the present invention is applied to a three-phase electric device, particularly a transformer. The relationship between injection of a pulse signal (simulated partial discharge signal) and a partial discharge detector calibrated thereby is shown.

  A similar circuit is shown in FIG. 18 for explaining a conventional partial discharge measuring apparatus, but FIG. 4 emphasizes that it is a three-phase circuit and adds a calibration signal injection part. FIG. 4 shows a circuit of a three-phase transformer connected by a Δ connection frequently used in a high-voltage three-phase circuit. In FIG. 4, high voltage windings 1U, 1V, 1W which are main circuit windings of the three-phase transformer are Δ-connected, and voltage switching tap terminals (5U, 5aU, 5V, 5aV, 5W, 5aW) are provided with partial discharge detectors 100U, 100V, 100W. 18 shows the high-voltage interphase lead 9 (9UV, 9VW, 9WU) for connecting the high-voltage winding terminals (4, 4a) of the high-voltage windings 1U, 1V, 1W between the phases. The high-pressure interphase lead 9 is not shown.

  In order to inject a calibration pulse signal, which is a simulated partial discharge signal, through the partial discharge detection unit 100U and calibrate the partial discharge detection unit 100W, as shown in FIG. 1, the partial discharge detection unit 100U (electrical conductor side device) The transmission antenna 301 of the above-described simulated partial discharge signal transmission unit 300 (ground side device unit) is disposed so as to face the antenna 101 of the unit.

Since the calibration pulse signal (pulse current) injected through the partial discharge detector 100U is a signal having a high rise characteristic, it propagates through the capacitance between the winding conductors rather than passing through the inductance of the winding conductor of the transformer. Cheap. There are two paths through the capacitance from the partial discharge detector 100U for injecting the calibration pulse signal to the partial discharge detector 100W to be calibrated, and the first path is a series of C1U and C2W in FIG. The second path is a series circuit of C2U, C1V, C2V, and C1W.

  FIG. 5 is a diagram showing an equivalent electric circuit in signal propagation from the transmitting end to the receiving end of the calibration pulse signal (simulated partial discharge signal) in the three-phase transformer, from the partial discharge detecting unit 100U at the transmitting end. The circuit which consists of said each capacitance in the signal propagation path to the partial discharge detection part 100W of a receiving end is shown. The calibration pulse signal injected into the partial discharge detection unit 100U as a pulse current is a current that passes through the tap terminals 5W and 5aW of the partial discharge detection unit 100W as it is through the transmission path. The tap terminals 5V and 5aV of the partial discharge detector 100V, which is a V-phase detection terminal, are between the above C1V and C2V, and the calibration pulse signal (pulse current) injected from the partial discharge detector 100U is also used as it is. Since it is in the path that passes, the partial discharge detectors 100W and 100V can both be calibrated by injection of a calibration pulse signal from the partial discharge detector 100U.

[Second Embodiment]
FIG. 6 is a diagram showing a configuration example of the second embodiment of the present invention, and shows an example of the overall configuration when the present invention is applied to a three-phase transformer. FIG. 7 is a diagram showing a partial discharge detector and a partial discharge receiver that form the partial discharge measurement system in the configuration example of FIG. Further, FIG. 8 is a diagram showing the configuration of the partial discharge detector in FIG.

The partial discharge measuring apparatus according to the present embodiment is different from the partial discharge measuring apparatus according to the first embodiment shown in FIGS. 1 and 2 in the following points, and is the same in other points.
(A) Configuration of the partial discharge detection unit (electrical conductor side device unit):
As shown in FIG. 8, the partial discharge detector 100A according to the second embodiment includes a ring-shaped core 11 made of a magnetic body that circulates the tap connection conductor 7 that is an electric path conductor portion through which a partial discharge current flows, A partial discharge detection unit according to the first embodiment includes a secondary winding 12 wound around a ring-shaped core and an antenna 101 that is an air-core coil and includes one or more air-core loop antennas. The capacitor 113 as in 100 (FIG. 20) is not provided. In the closed circuit including only the secondary winding 12 and the antenna 101 in the partial discharge detection unit 100A, the secondary winding 12 and the antenna 101 form a series circuit, but the partial discharge according to the first embodiment. A series resonance circuit of the secondary winding 12, the capacitor 113, and the antenna 101 as in the detection unit 100 (FIG. 20) is not formed.

(B) Configuration of the partial discharge receiver:
As shown in FIG. 7, the partial discharge receiving unit 200 </ b> A according to the second embodiment is an air-core coil arranged so that the magnetic field radiated from the transmission antenna 101 of the partial discharge detection unit 100 is linked. A receiving antenna 201 composed of one or more air core loop antennas, a matching unit 202 that matches the impedance of the receiving antenna 201 and the impedance of the transmission cable 203, a transmission cable 203, and a broadband amplifier that amplifies the received signal to a predetermined level 221 and a frequency-specific level measuring device 222 that can measure the frequency-specific level of the received signal by changing the measurement frequency with a certain bandwidth, and includes the frequency-specific level measuring device 222. Thus, it is different from the partial discharge receiver 200 (FIG. 19) according to the first embodiment.

The configuration of the simulated partial discharge signal transmission unit 300 in the present embodiment is the same as that in the first embodiment.
Further, FIG. 6 shows the apparatus configuration in the process of performing detection sensitivity calibration on the V and W phase sides by injecting calibration signals from the U phase side in the calibration work process of the partial discharge measuring apparatus, as in FIG. 1 described above. The phase in which the simulated partial discharge signal transmitter 300 and the partial discharge receiver 200A are provided is switched according to the progress of the calibration work process.

  And the partial discharge measuring apparatus by this embodiment makes high sensitivity by making the frequency with a high S / N ratio calculated | required in the detection sensitivity calibration process into the measurement frequency of the level measuring device 222 according to frequency so that it may mention later. Partial discharge measurement with a high S / N ratio can be performed.

(Measurement example of transfer characteristics of calibration pulse signal)
FIG. 9 shows a method for measuring the transfer characteristic of the calibration pulse signal in the partial discharge measuring apparatus according to the second embodiment of the present invention, and includes a set of antennas 101a for injecting the calibration pulse signal experimentally. 301, a terminal part (detector) 110Aa (right side in FIG. 9), a terminal part (detector) 110Ab on the calibration target side connected thereto via a capacitance Cs, and a pair of antennas 101b and 201 (left side in FIG. 9). It is a figure which shows an experimental circuit typically. Since the calibration pulse signal (pulse current) injected into the main circuit portion (electrical conductor portion) of the device under test is a signal having a high-speed rising characteristic, the transfer characteristic is determined by injecting the calibration pulse signal. This is the capacitance CS from the calibration end, which is a terminal portion, to the measurement end, which is the terminal portion to be calibrated, and this is used as a parameter in the experimental circuit of FIG.

  Among the antennas used in the experimental circuit of FIG. 9, the antennas 301 and 201 are both 11.5-turn loop antennas (Φ95 / 11.5T) having a diameter of 95 mm, and the antenna 101a is 5 times having a diameter of 95 mm. A wound loop antenna (Φ95 / 5T) was used, and the antenna 101b was a 5-turn loop antenna (Φ100 / 5T) having a diameter of 100 mm. The distance between the central axes of the calibration-end-side antenna pair 101a, 301 and the measurement-end-side antenna pair 101b, 201 is set to 400 mm, and an aluminum plate is provided between both antenna pairs. It was arranged so as to face the antenna pair on the side.

  The device portion in which the pulse power source 305 is connected to the antenna 301 in FIG. 9 via the series capacitor 304 corresponds to the simulated partial discharge signal transmission unit 300 (FIG. 6) in the present embodiment. 302 is not provided. 9 is equivalent to the partial discharge receiving unit 200A (FIG. 6 or FIG. 7) in this embodiment, but the matching unit 202 in FIG. 6 or FIG. 7 is provided. Also, an FET (field effect transistor) probe having a high input impedance and a low output impedance is used as the amplifier 221, and the output signal of the FET probe is displayed on a display unit such as an oscilloscope or a spectrum analyzer as will be described later. The received waveform and received signal spectrum of the detection signal corresponding to the calibration pulse signal are input and measured.

  In addition, in FIG. 9, the device portion in which the terminal portion (detector) 110Aa is connected to the antenna 101a and the device portion in which the terminal portion (detector) 110Ab is connected to the antenna 101b are the calibration end side in this embodiment, respectively. This corresponds to the partial discharge detector 100A on the calibration signal injection side and the measurement end side (the side to be calibrated), and includes a through-type current transformer including a ring-shaped core 11 and a secondary winding 12, and an antenna 101a. Alternatively, 101b is directly connected without interposing the capacitor 113.

  FIG. 10 is a diagram showing a measurement example of the received waveform of the detection signal corresponding to the calibration pulse signal in the experimental circuit of FIG. 9, and the measurement end side when a charge of 500 pC is injected from the calibration end side as the calibration pulse signal. The terminal voltage waveform of the receiving antenna 201 of the partial discharge receiver in FIG.

FIG. 11 is a diagram showing an example of measurement of the received signal spectrum of the detection signal corresponding to the calibration pulse signal by the experimental circuit of FIG. 9, and the terminal voltage when the terminal voltage of the receiving antenna 201 is viewed by frequency with a spectrum analyzer. And a result obtained by digitally converting a voltage waveform and obtaining a frequency component by performing FFT (Fast Fourier Transform). The upper diagram (spectrum of the received signal by the spectrum analyzer) and the lower diagram (spectrum of the received signal waveform by FFT) in FIG. 11 are obtained by measuring the same signal by changing the measurement method. It has become.

(How to obtain the optimum tuning frequency)
When looking at the magnitude of the measurement signal for each frequency with the spectrum analyzer (upper diagram in FIG. 11), the characteristic that the signal level is higher as the capacitance Cs from the calibration end to the measurement end is larger at 10 MHz or less. On the other hand, there is a maximum value with respect to the capacitance Cs at a frequency of 10 MHz or more. This characteristic is caused by resonance due to the inductance of the wiring coexisting with the capacitance Cs. In the actual measurement of partial discharge, there is a resonance frequency due to the inductance of winding conductors and connection conductors that are the main circuit parts (electric circuit conductors) of the electrical equipment for which partial discharge is to be measured. If detected, the measurement sensitivity of partial discharge can be improved. At that time, the tuning frequency to be selected can be measured with an excellent S / N ratio by considering not only the signal level but also the ratio of the magnitude to the background level when there is no calibration pulse signal.

  The above tuning frequency is determined as follows. In the detection sensitivity calibration process of the partial discharge measuring device, a calibration pulse signal is injected through the partial discharge detection unit of one phase (for example, U phase) and detected from the partial discharge detection unit of the other phase (for example, V phase or W phase). The output signal is received, and the received signal is input to a measuring instrument that can vary the measurement frequency in a certain band, such as a spectrum analyzer. The signal level by frequency when the calibration pulse signal is injected and the background level by frequency when the calibration pulse signal is not injected are read, the signal level is high, and the signal level and background A frequency having a high S / N ratio, which is a ratio of the magnitude to the level, is obtained. This frequency is the optimum tuning frequency.

  That is, for example, in the measurement example of FIG. 11, four peak frequencies of 8.2 MHz, 11.9 MHz, 16.9 MHz, and 19.2 MHz are obtained as frequencies common to the upper and lower diagrams. Since the N ratio is high, it is possible to obtain a result in which the sensitivity of the partial discharge signal with respect to the background noise is high by performing a measurement synchronized with the N ratio. Thus, in the present invention, the optimum tuning frequency can be quantitatively obtained from the signal level for each frequency in the detection signal corresponding to the calibration pulse signal and the background level. Each peak appearing in the spectrum of FIG. 11 is considered to be a resonance point generated from seven elements: four antennas, two pairs of antenna couplings, and an electric circuit of a high piezoelectric path.

  In the present embodiment, the circuit on the secondary winding side in the through-type current transformer of the partial discharge detector 100A (FIG. 8) is a closed circuit including only the secondary winding 12 and the antenna 101. Since it is not a series resonance circuit of the secondary winding 12, the capacitor 113, and the antenna 101 as in the partial discharge detector 100 (FIG. 20) of the embodiment, as a spectrum of the measurement signal when the calibration pulse signal is injected, As shown in FIG. 11 described above, a spectrum having a peak corresponding to the resonance frequency due to the inductance of the main circuit portion (electric circuit conductor) of the device under test is obtained.

(Partial discharge measurement with optimum tuning frequency)
In the detection sensitivity calibration process, a frequency with a high signal level and a high S / N ratio, which is a ratio of the signal level to the background level (hereinafter referred to as “high signal level / high S / N frequency”). When only one is obtained, the frequency is set to an optimum tuning frequency, and when a plurality of high signal levels and high S / N frequencies (peak frequencies) are obtained as shown in FIG. By selecting the frequency with the highest signal level giving priority to the signal level, selecting the frequency with the highest S / N ratio giving priority to the S / N ratio, etc. Find the optimal tuning frequency. Then, the actual partial discharge is measured in the actual partial discharge measurement process in a state where the one optimum tuning frequency thus obtained is set as the measurement frequency of the level measuring device 222 for each frequency in the partial discharge receiving unit 200A. Thus, partial discharge measurement with high sensitivity and high S / N ratio is possible.

  Here, for example, the above-described spectrum analyzer can be used as the level measuring device 222 for each frequency. However, the frequency measuring device 222 is not limited to the spectrum analyzer. Any configuration that can measure the level may be used. Note that the measurement operation performed in a state where the measurement frequency of the frequency level measuring instrument 222 is set to one optimum tuning frequency is performed by fixing the heterodyne frequency when the frequency level measuring instrument 222 is a spectrum analyzer, for example. It is an operation to observe.

  Further, in the present embodiment, as shown in FIG. 12, a signal processor 223 may be provided after the frequency level measuring device 222. FIG. 12 is a diagram showing a partial discharge detector and a partial discharge receiver that form a partial discharge measurement system in different configuration examples of the second embodiment of the present invention. The partial discharge receiving unit 200B in FIG. 12 has a configuration in which a signal processor 223 is added to the subsequent stage of the level measuring device 222 for each frequency with respect to the partial discharge receiving unit 200A in FIG. In the detection sensitivity calibration step, the signal processor 223 inputs the measurement output of the frequency-specific level measuring device 222, and the signal level for each frequency when the calibration pulse signal is injected and the calibration pulse signal are injected. The background level for each frequency is read, the signal level is high, and the frequency (high signal level / high S / high), which is the ratio of the signal level to the background level, is high. N frequency), and when multiple high signal levels and high S / N frequencies are obtained, the signal level is given priority to select the frequency with the highest signal level, or the S / N ratio. One optimal tuning frequency is obtained by, for example, selecting a frequency having the maximum S / N ratio with priority given to. Then, in the actual partial discharge measurement step, the signal processor 223 supplies the one optimum tuning frequency to the level-specific frequency measuring device 222 as a measurement frequency command value. Thus, in the actual partial discharge measurement step, partial discharge measurement with high sensitivity and high S / N ratio can be performed in a state where the measurement frequency of the level measuring device 222 for each frequency is set to one optimum tuning frequency.

  In the present embodiment, the signal processor 223 as in the configuration example of FIG. 12 is not necessarily required. In the detection sensitivity calibration process, the operator can obtain the high signal level and high level obtained by the frequency level measuring device 222. In addition to obtaining one optimum tuning frequency based on the S / N frequency, in the actual partial discharge measurement process, the operator sets the measurement frequency of the frequency level measuring instrument 222 by manual operation to the above tuning frequency. If the measurement operation by the frequency level measuring device 222 is performed, partial discharge measurement at an optimum tuning frequency can be performed.

(Effectiveness of FET probe)
Further, as shown in FIG. 9, in the partial discharge receiving unit including the receiving antenna 201 on the measurement end side, the amplifier 221 has a high input impedance and a low output impedance like the above-described FET (field effect transistor) probe. It is also effective to use an amplifier. As a result, it is possible to compensate for the disadvantage that impedance matching cannot be performed by the matching unit when the tuning frequency used for measurement changes due to the inductance of the main circuit portion (electric circuit conductor) of the device under test as described above. Since the input terminal of the FET normally has an input impedance with a resistance of 10 MΩ or more and a capacitance of 10 pF or less, the input impedance is sufficiently higher than the impedance of the loop antenna, and the induced electromotive force of the loop antenna is not reduced. In addition, the unnecessary resonance frequency due to the electrostatic capacitance component in the input impedance can be sufficiently increased to a frequency level that does not affect the measurement. In particular, when a measuring instrument that supports high frequencies such as a spectrum analyzer is used as a signal observation means, in order to avoid the influence of reflection at the input end of the measuring instrument itself, the input impedance of the measuring instrument is as low as about 50Ω. Therefore, it is a very effective means to perform impedance conversion using the above FET probe.

[Third Embodiment]
During normal operation of an electrical device such as a three-phase transformer that is the target of partial discharge measurement, a commercial frequency current of 50 to 60 Hz flows through the main circuit (electric circuit conductor). For this reason, when a high-frequency current transformer is used as a through-type current transformer of a partial discharge detection unit provided in a circuit conductor part such as a tap connection conductor, a low saturation magnetic flux unique to a magnetic circuit corresponding to a high frequency is used. Due to the problem, when the commercial frequency current is large, the ring-shaped core in the feedthrough current transformer becomes magnetically saturated, and the feedthrough current transformer is operated as a current transformer for detecting the partial discharge current. The detection sensitivity is lowered, and the calibration pulse signal cannot be injected even if the through-side current transformer is operated as a current transformer for injecting the calibration pulse signal.

  In order to avoid the above-described magnetic saturation in the feedthrough current transformer, for example, in the configuration of the partial discharge detector 100 shown in FIG. 20, the cross-sectional area of the ring-shaped core 11 is not magnetically saturated by the commercial frequency current. However, the through-type current transformer itself has a large physique and a high manufacturing cost, and the high-potential portion in the vicinity of the detector 110, that is, the tap terminals 5 and 5a becomes large. The overall configuration of the discharge measuring apparatus is increased in size, which causes a problem in equipment installation space. For this reason, even if the ring-shaped core 11 is small, it is necessary to take measures to prevent magnetic saturation due to the commercial frequency current.

  In this regard, paying attention to the fact that the commercial frequency current is 3 digits or more away from the high-frequency current due to partial discharge, a compensation winding wound in a toroidal manner like a secondary winding on a ring-shaped core By providing a current in a direction that cancels the commercial frequency component in the compensation winding, the magnetic flux of the commercial frequency component in the ring core is canceled and the ring core is prevented from becoming magnetically saturated. Therefore, even if the electrical equipment to be measured, such as a three-phase transformer, is energized and a large commercial frequency current is flowing through the main circuit (electric circuit conductor), the partial discharge current is reduced by the through-type current transformer. Detection and calibration pulse signals can be injected.

  As an example of a specific configuration for preventing magnetic saturation using the compensation winding as described above, a filter winding for winding a ring-shaped core is provided, and a low-pass that allows a commercial frequency band to pass through both ends of the filter winding. If the input end of the filter is connected, and the load circuit that supplies the current in the commercial frequency band is connected to the output end of the low-pass filter, the commercial frequency component flows to the load circuit via the low-pass filter. Current flows in the direction of the commercial frequency component in the direction to cancel the magnetic flux in the ring-shaped core, so that the magnetic flux in the ring-shaped core is canceled even if a large current of commercial frequency flows in the circuit conductor part such as the tap connection conductor. As a result, the ring-shaped core is not magnetically saturated.

  FIG. 13 is an explanatory diagram of a partial discharge detection unit in the partial discharge measurement device according to the third embodiment of the present invention, to which the configuration in which the filter winding is provided as described above, and FIG. It is a block diagram of the said partial discharge detection part. The partial discharge measurement device according to the third embodiment is different from the partial discharge measurement device according to the first embodiment shown in FIGS. 1 and 2 in the filter discharge 121, the low-pass filter 122, and the load circuit 123 in the partial discharge detection unit. Are different, and the other configurations are the same. In addition to the secondary winding 12, a filter winding 121 is wound around the ring-shaped core 11 of the detector 110 </ b> B, and an input end of a low-pass filter 122 that passes a commercial frequency band at both ends of the filter winding 121. Is connected. A load circuit 123 for supplying a current in the commercial frequency band is connected to the output terminal of the low-pass filter 122. Since the commercial frequency component flows to the load circuit 123 via the low-pass filter 122, the commercial frequency component current flows in the filter winding 121 in a direction to cancel the magnetic flux in the ring-shaped core 11. Therefore, even if a large current having a commercial frequency is passed through the tap connection conductor 7, the magnetic flux in the ring-shaped core 11 is canceled and the ring-shaped core 11 is not magnetically saturated. On the other hand, the magnetic flux of high frequency components of several tens of kilohertz or more, which is the frequency band of partial discharge, is not canceled out. For this reason, there is no problem in the detection of the partial discharge current and the injection of the calibration pulse signal by the through-type current transformer. As a result, the physique of the detector 110B is reduced, and its production cost is reduced. In addition, the high voltage portion in the vicinity of the tap terminals 5 and 5a is reduced, the overall configuration of the partial discharge measuring device is reduced in size, and the equipment installation space can be reduced.

  FIG. 13B is a characteristic diagram showing the pass characteristics of the low-pass filter 122 of FIG. The horizontal axis shows the frequency f, and the vertical axis shows the passage amount (ratio of the output voltage V2 to the input voltage V1, V2 / V1). The characteristic is as indicated by 129, and a frequency component equal to or lower than the cutoff frequency fc is passed. In this case, the cutoff frequency fc is set higher than the commercial frequency and lower than several tens of kilohertz.

  FIG. 13C is a circuit diagram illustrating a configuration example of the low-pass filter 122 of FIG. A low-pass filter 122 is formed in a T shape with inductances 125 and 126, a resistor 124, and a capacitance 127, a filter winding 121 is connected to an input end, and a resistor 128 as a load circuit 123 is connected to an output end. In this circuit, when it is desired to set the cutoff frequency to fc, the resistance values of the resistors 124 and 128 are both R, the capacitance of the capacitance 127 is 2 / (R · fc), and the self-inductances of the inductances 125 and 126 are both R / fc. Choose to be

  The partial discharge detector 100A (FIG. 8) in the second embodiment is also provided with a filter winding 121 around which the ring-shaped core 11 is wound, similar to the present embodiment, and both ends of the filter winding 121. A configuration in which the input terminal of the low-pass filter 122 that passes the commercial frequency band is connected, and the load circuit 123 that flows the current in the commercial frequency band to the output terminal of the low-pass filter 122 can be applied. Even when a large commercial frequency current is flowing through the main circuit (electric circuit conductor) of the target electrical device, it is possible to detect a partial discharge current and to inject a calibration pulse signal using a feedthrough current transformer.

[Fourth Embodiment]
In addition, as another example of a specific configuration for preventing magnetic saturation using the compensation winding as described above, a configuration may be adopted in which a ring-shaped core is wound and a short-circuit winding with both ends short-circuited is provided. Because the inductance, conductor resistance, and turn-to-turn capacitance of the short-circuit winding itself constitute a low-pass filter and load circuit, the commercial frequency component current flows in the direction of canceling the magnetic flux in the ring-shaped core through the short-circuit winding, and the tap Even if a large current of a commercial frequency flows through a conductor portion such as a connection conductor, the magnetic flux in the ring core is canceled and the ring core does not become magnetically saturated.

  FIG. 14 is a configuration diagram of a partial discharge detector in the partial discharge measuring apparatus according to the fourth embodiment of the present invention, to which the short-circuit winding as described above is applied. The partial discharge measuring apparatus according to the fourth embodiment is different from the partial discharge measuring apparatus according to the first embodiment shown in FIGS. 1 and 2 in that a short-circuit winding 141 is provided in the partial discharge detector. Other configurations are the same. In addition to the secondary winding 12, a short-circuit winding 141 short-circuited at both ends is wound around the ring-shaped core 11 of the detector 110 </ b> C. The circuit on the short-circuit winding 141 side is equivalent to the circuit of the low-pass filter of FIG. 13C, and the self-inductance, conductor resistance, and capacitance between turns (capacitance) of the short-circuit winding 141 itself. ) Constitute the inductances 125 and 126, the resistors 124 and 128, and the capacitance 127 of FIG. 13C, respectively. Therefore, even if a large current flows through the tap connection conductor 7 penetrating the ring-shaped core 11, the magnetic flux in the ring-shaped core 11 is canceled and the iron core is not magnetically saturated. On the other hand, a high frequency component of several tens of kilohertz or more which is a frequency band of partial discharge is not canceled. For this reason, there is no problem in the detection of the partial discharge current and the injection of the calibration pulse signal by the through-type current transformer. As a result, the physique of the detector 110C is reduced, and its production cost is reduced. In addition, the high voltage portion in the vicinity of the tap terminals 5 and 5a is reduced, the overall configuration of the partial discharge measuring device is reduced in size, and the equipment installation space can be reduced.

    In addition, the configuration provided with the short-circuit winding 141 that winds the ring-shaped core 11 similar to the present embodiment can be applied to the partial discharge detection unit 100A (FIG. 8) in the second embodiment, As a result, even when a large commercial frequency current is flowing in the main circuit (electric circuit conductor) of the electrical equipment to be measured, it is possible to detect a partial discharge current and inject a calibration pulse signal using a feedthrough current transformer. It becomes.

[Applicable objects of the present invention]
In the above-described embodiment, the partial discharge detection unit in the partial discharge measuring device of the type that transmits a detection signal as a magnetic field mainly for a three-phase device, particularly a three-phase transformer among electric devices, A set of each set is provided in each phase, and the partial discharge detector provided in one of the phases is used to inject a calibration pulse signal that is a simulated partial discharge signal, and is detected by a partial discharge detector provided in another phase. Thus, the configuration for calibrating the detection sensitivity of the device provided in the detection phase has been described.

  When the device under test is a three-phase device such as a three-phase transformer, the main circuits (electric circuit conductors) of each phase are structurally and electrically adjacent to each other, corresponding to the fast rise characteristics of the calibration pulse signal. Since the capacitive coupling between the main circuits (electric circuit conductors) of each phase in the high-frequency region is large, in the propagation of the calibration pulse signal between the main circuits (electric circuit conductors) of each phase, A sufficiently large pulse current can be passed compared to external noise. In addition, since the capacitive coupling between the main circuits (electric circuit conductors) of each phase is large, the impedance from the electric circuit conductor part of the phase into which the calibration pulse signal is injected to the electric circuit conductor part of the other phase to be calibrated Is lower than the impedance to the external circuit conductor part of the device under test, the calibration pulse signal injected into one phase of the three-phase circuit uses the circuit conductor part of the other phase as the pulse current and the reciprocal of the above impedance ratio. Therefore, the influence from devices other than the device to be measured and the device in calibration of detection sensitivity can be reduced. Therefore, the partial discharge measuring apparatus, the partial discharge measuring apparatus calibration method, and the partial discharge measuring method according to the present invention can be suitably applied when the device under measurement is a three-phase device.

  In addition, when the device under test is a three-phase transformer in particular, a high-speed rise characteristic calibration pulse can be obtained due to the presence of capacitance between winding conductors (between turns) in the main circuit winding of each phase. The impedance of the main circuit windings of each phase with respect to the signal is low, and the main circuit windings are connected to each other from the circuit conductor part where the partial discharge detection part, such as a voltage switching tap terminal, is provided. Since the impedance to the conductor portion is low, the impedance from the circuit conductor portion of the phase where the calibration pulse signal is injected to the circuit conductor portion of the other phase to be calibrated is particularly low, and the present invention is particularly suitable. Can be applied.

  However, the partial discharge measurement device according to the present invention, the calibration method of the partial discharge measurement device, and the electrical device that is the target of the partial discharge measurement method are not limited to three-phase devices such as a three-phase transformer, The present invention is applicable to multiphase devices other than three phases as long as it is a configuration in which two or more circuit conductor portions provided with partial discharge detectors are capacitively coupled to each other. Furthermore, the present invention can be applied to a single-phase device such as a single-phase transformer having two windings.

  Then, the partial discharge measuring device, the partial discharge measuring device calibration method and the partial discharge measuring method according to the present invention include, as targets, other than transformers such as instrument transformers (PT) and instrument current transformers (CT). The present invention can be suitably applied to an induction electric machine having an electromagnetic induction winding, and can be widely applied to all electric devices such as a switch having a conductor portion charged to a high voltage.

  The present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention.

It is a figure which shows the structural example of the 1st Embodiment of this invention. It is a figure which shows the partial discharge detection part and the simulation partial discharge signal transmission part in the structural example of FIG. It is a figure which shows the structure of the antenna pair in the structural example of FIG. It is a figure which shows the electric circuit used as the transmission path | route of the calibration pulse signal in a three-phase transformer. It is a figure which shows the equivalent circuit of the transmission path from the transmission end of a calibration pulse signal in a three-phase transformer to a reception end. It is a figure which shows the structural example of the 2nd Embodiment of this invention. It is a figure which shows the partial discharge detection part and partial discharge receiving part in the structural example of FIG. It is a figure which shows the structure of the partial discharge detection part in FIG. It is a figure which shows typically the experimental circuit of the partial discharge measuring apparatus by the 2nd Embodiment of this invention. It is a figure which shows the example of a measurement of the received waveform of the calibration pulse signal by the experimental circuit of FIG. It is a figure which shows the example of a measurement of the received signal spectrum of the calibration pulse signal by the experimental circuit of FIG. It is a figure which shows the partial discharge detection part and the partial discharge receiving part in the structural example from which the 2nd Embodiment of this invention differs. It is a figure which shows the structure of the partial discharge detection part in the 3rd Embodiment of this invention. It is a figure which shows the structure of the partial discharge detection part in the 4th Embodiment of this invention. It is a figure which shows the external appearance of a mold transformer, and the connection terminal with the exterior. It is a figure which shows the structure of the partial discharge measuring apparatus of the conventional mold transformer. It is a figure which shows the structure of the partial discharge detection part in the partial discharge measuring apparatus of FIG. It is a figure which shows the connection of the partial discharge measuring apparatus of FIG. 16, and the high voltage | pressure winding of a three-phase mold transformer. It is a figure which shows the partial discharge detection part and the partial discharge receiving part in the partial discharge measuring apparatus of a prior application (Japanese Patent Application No. 2006-263668). It is a figure which shows the structure of the partial discharge detection part in the partial discharge measuring apparatus of a prior application (Japanese Patent Application No. 2006-263668). It is a figure which shows an example of a calibration circuit in principle.

Explanation of symbols

1 High voltage winding 2 Iron core 3, 3a Frame 4, 4a High voltage winding terminal (electric circuit connection terminal)
5, 5a Tap terminal 6 High voltage interphase lead connection (high voltage winding connector)
7 Tap connection conductor 8 High voltage bus (high piezoelectric conductor)
9 High-voltage interphase lead (winding connection crossing conductor)
DESCRIPTION OF SYMBOLS 10 Detector 11 Ring-shaped core 12 Secondary winding 13 Capacitor 20 Electrical-optical converter 21 Amplification part 22 Electrical-optical conversion part 25 Partial discharge detection part 30 Optical cable 41 Optical-electrical converter 42 Main amplifier 43 Display part 45 Part Discharge receiving unit 100, 100A Partial discharge detecting unit 101 Air core coil (electrical conductor side antenna)
110, 110A, 110B, 110C Detector 113 Series capacitor 121 Compensation winding 122 Low pass filter 123 Load circuit 141 Short-circuit winding 200, 200A, 200B Partial discharge receiver 201 Air-core coil (receiving antenna)
202 Matching Unit 203 Transmission Cable 204 Preamplifier 205 Main Amplifier 206 Display Unit 221 Amplifier 222 Frequency Measuring Unit 223 Signal Processor 300 Simulated Partial Discharge Signal Transmitter 301 Air-core Coil (Transmission Antenna)
302 Matching device 303 Transmission cable 304 Series capacitor 305 Pulse power supply

Claims (12)

A partial discharge measuring device for measuring a partial discharge generated inside an electrical device,
A ring formed of a magnetic material that circulates in an electric circuit conductor portion through which a partial discharge current generated by the partial discharge flows out of an electric conductor formed of a conductor provided in the electric device and / or an external conductor connected to the electric device. A core, a secondary winding wound around the ring-shaped core, and an electric conductor-side antenna composed of an air-core coil, and forming a series circuit of the secondary winding and the electric conductor-side antenna Each of the electric circuit conductor side device section is provided in two or more electric circuit conductor sections that are capacitively coupled in the electric circuit conductor,
The first electric circuit conductor side device provided in one of them is used as a simulated partial discharge signal receiving unit, and a simulated partial discharge signal simulating partial discharge is received from the outside via the electric conductor side antenna,
By making the second electric circuit conductor side device part provided in the other part a partial discharge detection part and transmitting the partial discharge detection signal to the outside via the electric circuit conductor side antenna,
A partial discharge measuring device characterized in that calibration of detection sensitivity can be performed when the second electric path conductor side device is a partial discharge detector. A ground-side antenna composed of an air-core coil arranged at a spatial distance facing the circuit-conductor-side antenna of the first circuit-conductor-side device unit, and supplying a pulse current as a simulated partial discharge signal to the ground-side antenna A first ground-side device section serving as a simulated partial discharge signal transmitting section that transmits a simulated partial discharge signal via a ground-side antenna,
A grounding antenna composed of an air-core coil disposed at a spatial distance facing the circuit conductor side antenna of the second circuit conductor side device unit, and amplification for amplifying and displaying a signal from the grounding antenna A second ground-side device unit that is a partial discharge receiving unit that includes a display unit and receives a partial discharge detection signal via the ground-side antenna;
Calibration of detection sensitivity when the first and second grounding side device units are the simulated partial discharge signal transmitting unit and the partial discharge receiving unit, respectively, and the second circuit conductor side device unit is the partial discharge detection unit. The partial discharge measuring device according to claim 1, wherein the partial discharge measuring device can be performed. A set of configurations including the first electric conductor-side device unit and the ground-side antenna of the first ground-side device unit is composed of the second electric conductor-side device unit and the ground side of the second ground-side device unit. By having the same configuration as a set of antennas,
Calibration of detection sensitivity when the first and second grounding side device units are the simulated partial discharge signal transmitting unit and the partial discharge receiving unit, respectively, and the second circuit conductor side device unit is the partial discharge detection unit. As well as
The simulated signal generating unit in the first ground side device unit and the amplification display unit in the second ground side device unit are recombined with each other, and the first and second ground side device units are respectively replaced with the partial discharge receiving unit and the simulated part. 3. The portion according to claim 2, wherein the detection sensitivity can be calibrated when the first circuit conductor side device unit is a partial discharge detection unit in a state where the discharge signal transmission unit is used. Discharge measuring device. The electrical device has a three-phase circuit,
4. The partial discharge measuring device according to claim 3, wherein a set of configurations including an electric conductor-side device unit and a ground-side antenna of the ground-side device unit is provided in each phase of the three-phase circuit. A ring-shaped core made of a magnetic body that circulates around the electric circuit conductor part, the electric circuit conductor side device part;
A secondary winding wound around the ring-shaped core, a capacitor, and an electric conductor-side antenna comprising an air-core coil, and a series resonance circuit of the secondary winding, the capacitor, and the electric conductor-side antenna The partial discharge measuring device according to claim 1, wherein the partial discharge measuring device is formed. In the amplification display unit of the second ground side device unit that receives the partial discharge detection signal transmitted from the second circuit conductor side device unit serving as the partial discharge detection unit as a reception signal,
A frequency-specific level measuring means capable of inputting the received signal and measuring a frequency-specific level of the received signal by changing a measurement frequency with a certain bandwidth;
In the detection sensitivity calibration step for calibrating the detection sensitivity when the second circuit conductor side device unit is the partial discharge detection unit, the measurement output of the frequency level measuring means is input and the simulated partial discharge signal is injected. The signal level for each frequency when the signal is generated and the background level for each frequency when the simulated partial discharge signal is not injected are read, the signal level is high, and the signal level and the background level are large. In the actual partial discharge measurement step of measuring the actual partial discharge in a state where the second electric path conductor side device unit is the partial discharge detection unit, the frequency with a high S / N ratio which is the ratio of A signal processing means for providing a tuning frequency as a command value of the measurement frequency to the level measuring means for each frequency, and
3. The partial discharge measuring device according to claim 2, wherein an actual partial discharge can be measured in a state where the measurement frequency of the level measuring means for each frequency is set to the tuning frequency. A calibration method in a partial discharge measuring device for measuring a partial discharge generated inside an electrical device,
A ring formed of a magnetic material that circulates in an electric circuit conductor portion through which a partial discharge current generated by the partial discharge flows out of an electric conductor formed of a conductor provided in the electric device and / or an external conductor connected to the electric device. A core, a secondary winding wound around the ring-shaped core, and an electric conductor-side antenna composed of an air-core coil, and forming a series circuit of the secondary winding and the electric conductor-side antenna Each of the electric circuit conductor side device section is provided in two or more electric circuit conductor sections that are capacitively coupled in the electric circuit conductor,
The first electric circuit conductor side device provided in one of them is used as a simulated partial discharge signal receiving unit, and a simulated partial discharge signal simulating partial discharge is received from the outside via the electric conductor side antenna,
By making the second electric circuit conductor side device part provided in the other part a partial discharge detection part and transmitting the partial discharge detection signal to the outside via the electric circuit conductor side antenna,
A calibration method of a partial discharge measuring device, wherein calibration of detection sensitivity is performed when the second electric path conductor side device unit is a partial discharge detection unit. A ground-side antenna composed of an air-core coil arranged at a spatial distance facing the circuit-conductor-side antenna of the first circuit-conductor-side device unit, and supplying a pulse current as a simulated partial discharge signal to the ground-side antenna A first ground-side device section serving as a simulated partial discharge signal transmitting section that transmits a simulated partial discharge signal via a ground-side antenna,
A grounding antenna composed of an air-core coil disposed at a spatial distance facing the circuit conductor side antenna of the second circuit conductor side device unit, and amplification for amplifying and displaying a signal from the grounding antenna A second ground-side device section that is a partial discharge receiving section that includes a display section and that receives a partial discharge detection signal via a ground-side antenna;
Calibration of detection sensitivity when the first and second grounding side device units are the simulated partial discharge signal transmitting unit and the partial discharge receiving unit, respectively, and the second circuit conductor side device unit is the partial discharge detection unit. The method for calibrating a partial discharge measuring device according to claim 7, wherein the method is performed. A set of configurations including the first electric conductor-side device unit and the ground-side antenna of the first ground-side device unit is composed of the second electric conductor-side device unit and the ground side of the second ground-side device unit. The same configuration as a set of antennas,
Calibration of detection sensitivity when the first and second grounding side device units are the simulated partial discharge signal transmitting unit and the partial discharge receiving unit, respectively, and the second circuit conductor side device unit is the partial discharge detection unit. As well as
The simulated signal generating unit in the first ground side device unit and the amplification display unit in the second ground side device unit are recombined with each other, and the first and second ground side device units are respectively replaced with the partial discharge receiving unit and the simulated part. 9. The method for calibrating a partial discharge measuring device according to claim 8, wherein the detection sensitivity is calibrated when the first circuit conductor side device unit is a partial discharge detection unit in a state where the discharge signal transmission unit is used. . The electrical device has a three-phase circuit,
A set of configurations consisting of a circuit conductor side device unit and a ground side antenna of the ground side device unit is provided for each phase of the three-phase circuit,
A simulated signal generator is connected to a set of any one of the three phases, and the ground side device unit of this phase is used as a simulated partial discharge signal generator, and the circuit conductor side device unit of the other phase is a part. 10. The method for calibrating a partial discharge measuring apparatus according to claim 9, wherein calibration of detection sensitivity when the discharge detector is used is performed. The electric circuit conductor side device section is a ring-shaped core made of a magnetic material that circulates around the electric circuit conductor section, a secondary winding wound around the ring-shaped core, a capacitor, and an electric conductor side that includes an air-core coil. The partial discharge measurement according to any one of claims 7 to 10, further comprising an antenna, and forming a series resonance circuit of the secondary winding, the capacitor, and the antenna on the electric conductor side. Device calibration method. A partial discharge measuring method for measuring a partial discharge generated inside an electrical device using the partial discharge measuring device according to claim 2,
The amplification display unit of the second ground side device unit that receives the partial discharge detection signal transmitted from the second circuit conductor side device unit serving as the partial discharge detection unit as a reception signal has a measurement frequency with a certain bandwidth. Providing a frequency-specific level measuring means capable of changing the frequency-dependent level of the received signal and allowing the frequency-dependent level measuring means to input the received signal;
In the detection sensitivity calibration step of calibrating the detection sensitivity when the second circuit conductor side device unit is the partial discharge detection unit, the signal level for each frequency when the simulated partial discharge signal is injected, and the simulation Reads the background level for each frequency when the partial discharge signal is not injected, and tunes the frequency with a high signal level and a high S / N ratio, which is the ratio of the signal level to the background level. As a frequency, then
In an actual partial discharge measurement step of measuring an actual partial discharge in a state where the second circuit conductor side device unit is a partial discharge detection unit, the measurement frequency of the level measuring means for each frequency is set to the tuning frequency and the partial discharge is performed. A partial discharge measuring method characterized by performing measurement.

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