JP3294806B2 - Partial discharge detector for gas insulated electrical equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detection device for a gas-insulated electric device such as a gas-insulated switchgear, and more particularly, to simplifying the detection and improving the accuracy.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a configuration diagram showing a partial discharge detection device for a conventional gas insulated electric device of this kind described in Japanese Patent Application Publication No. 09-0909. In the figure, 1 is a metal container containing a conductor 2 which is a main body of the device together with an insulating gas, 3 is an insulating spacer, 4 is a bushing, 5 is an electromagnetic wave sensor, 6 is an electromagnetic wave generator, 7 is an electromagnetic wave sensor, and 8 is an amplifier. , 9 are spectrum analyzers, 1
0 is a computer.

Next, the operation will be described. An electromagnetic wave generator 6 generates an electromagnetic wave of 0 to 1 GHz to generate an electromagnetic wave sensor 5.
Radiates into the metal container 1. This electromagnetic wave is detected by the electromagnetic wave sensor 7, the electromagnetic wave signal is amplified by the amplifier 8, the spectrum is analyzed by the spectrum analyzer 9, and the spectrum is stored in the computer 10. An example of the spectrum obtained at this time is shown in FIG. Next, an example of a spectrum when a partial discharge occurs in the metal container 1 is shown in FIG.

When an electromagnetic wave is generated inside the metal container 1,
The resonance frequency fn determined by the length L of the conductor 2 = (C /
2L) n occurs and the frequency spectrum is strengthened. Here, C is the speed of light, and n is a natural number. The computer 10 confirms that the frequency at which the spectrum intensity of the electromagnetic wave is large matches the resonance frequency, compares the two spectra, and determines the occurrence of partial discharge inside the metal container 1.

[0005]

The conventional partial discharge detecting device is constructed as described above. Of the electromagnetic wave signal generated by the partial discharge, the spectrum component in the frequency band of 0 to 1 GHz or the spectrum containing this frequency band is used. Component was detected. The spectrum of the frequency handled by this method is affected by the shape and structure of the gas insulated switchgear, such as the outer diameter of the conductor 2, the inner diameter of the metal container 1, and the mounting interval of the insulating spacer 3, when a discharge occurs. As shown in FIG. 15, the spectrum distribution has a large difference between resonance and antiresonance. Therefore, it is necessary to calibrate the electromagnetic wave sensor every time the structure of the gas insulated switchgear is different, and it is necessary to check the relationship between the electromagnetic wave sensor and the amount of partial discharge charge every time.

Further, since the conventional partial discharge detection device determines the presence or absence of a partial discharge by focusing on the spectrum of a specific single frequency at which resonance is confirmed, when the resonance frequency is slightly shifted, There was a risk of making a mistake in the judgment.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and is intended to provide a gas that can easily and accurately detect a partial discharge without being substantially affected by the structure of each device. An object is to obtain a partial discharge detection device for insulated electric equipment.

[0008]

According to a first aspect of the present invention, there is provided an apparatus for detecting partial discharge of a gas-insulated electrical device, comprising: means for detecting an electromagnetic wave generated inside the gas-insulated electrical device; In the partial discharge detection device for a gas-insulated electric device, which detects a partial discharge generated inside the gas-insulated electric device, the detection frequency of the electromagnetic wave detecting means is set to the TM wave (the electric field is the traveling direction, the magnetic field Is a frequency region higher than the cut-off frequency of a component perpendicular to the traveling direction).

According to a second aspect of the present invention, the detection frequency of the electromagnetic wave detecting means is set to 1 GHz or more.

A partial discharge detecting device for a gas insulated electric device according to a third aspect of the present invention includes an antenna for receiving an electromagnetic wave and a spectrum analyzer for obtaining a spectrum distribution of an output of the antenna, as a means for detecting the electromagnetic wave. The spectrum integrated value obtained by integrating the spectral components in the frequency domain is obtained when the partial discharge of the gas-insulated electrical equipment is detected and when no charge is applied or when the known charge is partially discharged. Or the detection of the amount of partial discharge generated charge.

The spectral integrated value of the partial discharge detecting device for gas-insulated electrical equipment according to the fourth aspect is an arithmetic operation of a value obtained by integrating values of spectral components in a plurality of predetermined frequency regions excluding a frequency region where external noise exists. It is a sum.

According to a fifth aspect of the present invention, there is provided an apparatus for detecting partial discharge of a gas-insulated electric device, wherein an antenna for receiving an electromagnetic wave and a signal having a frequency equal to or higher than a predetermined frequency are inserted at an output side of the antenna. A high-pass filter and an amplifier inserted on the output side of the high-pass filter, and determine an output value from the amplifier when a partial discharge of the gas-insulated electric device is detected and when no charge is applied or when a known charge is partially discharged. The determination of the occurrence of partial discharge or the detection of the amount of charge generated by partial discharge is performed from the obtained output values.

According to a sixth aspect of the present invention, there is provided a partial discharge detection device for a gas insulated electric device, as an electromagnetic wave detecting means, which excludes an antenna for receiving an electromagnetic wave and a frequency region inserted into an output side of the antenna and having external noise. A bandpass filter that allows a signal in a predetermined frequency range to pass therethrough, and an amplifier inserted on the output side of the bandpass filter,
The output value from the amplifier is determined when detecting partial discharge of the gas-insulated electrical device and when no power is applied or when a known amount of electric charge is partially discharged. The charge amount is detected.

According to a seventh aspect of the present invention, there is provided a partial discharge detection device for a gas insulated electric device, wherein the unit body is housed in a container formed by connecting a plurality of unit containers via insulating spacers. The electromagnetic wave detecting means according to claim 1 is attached to an outer periphery of the insulating spacer,
A position where a partial discharge occurs in the gas-insulated electric device is determined from a relative comparison between detection signals of the electromagnetic wave detection means in the insulating spacers.

According to an eighth aspect of the present invention, there is provided a partial discharge detection device for a gas-insulated electric device, wherein a partial potential of a capacitor between a high potential of the device main body and a ground potential of the container is provided in a part of the container of the gas-insulated electric device. An internal electrode that outputs an intermediate potential is provided,
An internal electrode type partial discharge detection device that detects a partial discharge generated inside the gas-insulated electric device based on a detection signal in a frequency region of less than 1 GHz of the output of the internal electrode; When a partial discharge is detected, a partial discharge occurrence position according to claim 7 is determined.

According to a ninth aspect of the present invention, the detection frequency of the electromagnetic wave detecting means is 1.2 GHz or more.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram showing a partial discharge detection device of a gas-insulated electric device according to Embodiment 1 of the present invention. In the figure, reference numeral 11 denotes a metal container in which a conductor 12 serving as a device main body is housed together with SF ₆ gas serving as an insulating gas, 13 denotes an insulating spacer inserted into a connecting portion of the metal container 11, and 14 denotes a device connecting the device body and the outside. This is a bushing for making a connection.

Reference numeral 15 denotes an antenna that receives electromagnetic waves generated inside the metal container 11 and leaks from the insulating spacer 13 into the air, 16 denotes an amplifier that amplifies the output from the antenna 15, and 17 denotes a spectrum of the output from the amplifier 16. A spectrum analyzer 18 for obtaining a distribution, an operation device 18 for performing operations such as spectrum integration described later, and a storage device 19 for storing various operation data.

Hereinafter, the configuration and operation of the partial discharge detection device will be described in detail. First, the process of completing the present invention will be described. In other words, the inventors have focused on the form of electromagnetic wave propagation due to partial discharge generated inside gas-insulated electrical equipment and the characteristics of each component of the electromagnetic wave in order to solve the above-described problems, and have conducted various experiments and analysis results. A component of electromagnetic waves which does not affect the structure of the device was found, and a frequency range to be detected was determined accordingly. Hereinafter, the mode of propagation of the electromagnetic wave and the characteristics of each component of the electromagnetic wave will be described first, and then the contents of a specific configuration example will be described.

FIG. 2 deals with a typical partial discharge model. That is, as shown in FIG. 2A, a conductor is disposed on the inner central axis of a cylindrical sheath which is a metal container of the gas insulated switchgear GIS, and a floating electrode is present on the inner surface of the sheath. It is assumed that discharge occurs between the gap between the electrode and the floating electrode.

FIG. 2B shows an electrical equivalent circuit at this time. In the figure, the capacitance formed between the conductor A and the floating electrode D is C1, the capacitance formed between the sheath B and the floating electrode D is C2, and the capacitance formed between the conductor A and the sheath B is C0 and G.
Assume that the impedance when Z is regarded as a distributed constant line is Z, and the discharge is simulated by ON / OFF of a switch.

When a voltage V is applied between the conductor A and the sheath B, voltages V1 and V2 are applied to both ends of the capacitors C1 and C2, respectively, and electric charges q1 and q2 are stored, respectively. Only q0 = C0 × V is stored in the capacitor C0. Then, when the voltage V2 reaches a certain voltage ΔV, the battery is discharged (the switch is turned on), and the charge q2 is lost. Here, since the charge q2 is a charge of the discharge itself, it is called a true discharge charge (or a moving charge). Also,
By discharging, the voltage V2 becomes zero, and the voltage applied to the capacitance C1 and the voltage applied to the capacitance C0 try to become the same voltage.
It is displaced to (q1 + q0) / (C1 + C0), and then returns to the applied voltage V again. Due to the displacement potential between the conductor A and the sheath B, a pulse is generated between the conductor A and the sheath B, and propagates on the distributed constant line. At this time, the charge of the current pulse flowing through the conductor is referred to as an apparent discharge charge here.

This apparent discharge charge has the shape of GIS,
When the values of the capacitances C1 and C0 and the impedance Z change due to a different structure, the value of the charge also changes.
It is constant regardless of the IS shape and structure. As will be described later, in the conventional partial discharge detection method, since this apparent discharge charge is detected, it is necessary to configure the sensitivity of the electromagnetic wave sensor for each different GIS structure.

By the way, when a partial discharge occurs in the GIS, an electromagnetic wave is radiated from the minute change current portion, and it is known that the electromagnetic wave propagates in the GIS. The micro-change current sources that cause this electromagnetic wave include the above-described true discharge charges and apparent discharge charges. Electromagnetic waves generated by apparent discharge charges propagating in a conductor are TEM waves (waves having no electromagnetic wave component in the traveling direction, Transverse Ele
ctro Magnetic wave, which is a TE wave (magnetic wave travels in the direction of travel, electric field travels in a direction perpendicular to the direction of travel, Transverse Electri)
c wave) and TM wave (the electric field travels in the direction of travel, the magnetic field travels in a direction perpendicular to the direction of travel, TransvevseMagnetic wav
e).

A TEM wave generated by a partial discharge in a gas has a spectrum component in a wide band from a low frequency to a high frequency, and the spectrum intensity decreases as the frequency increases, and exists around 1 GHz (see FIG. 1). 3
(A)). On the other hand, the TE wave and the TM wave
S has a cutoff frequency determined by the structure of S, and has spectral components up to several GHz after this cutoff frequency (FIG. 3).
(B)).

The cut-off frequency is the lowest frequency (longest wavelength) that can exist, which is determined by the outer shape of the waveguide, in this case, the conductor 12 and the inner diameter of the sheath that is the metal container 11, and is the TE wave, The cut-off frequency of the TM wave is approximately obtained by the following equation.

Cut-off frequency of TE wave fec = V / λec where λec = π (a + b) Cut-off frequency of TM wave fmc = V / λmc where λmc = 2 (ba) where V is the propagation speed of the electromagnetic wave , A is the radius of the metal container,
b is a sheath radius.

In a general structure of a gas insulated switchgear (GIS), the cut-off frequency fec of the TE wave is 100 to 500.
MHz, TM wave cutoff frequency fmc = 600-900M
Hz.

FIG. 3C shows a combination of the three components of the electromagnetic wave, that is, the TEM wave, the TE wave and the TM wave. As can be seen, in the relatively low frequency region, the TEM wave and the TE wave are mixed, and the signal component depending on the true discharge charge and the signal component existing in the apparent discharge charge are mixed. On the other hand, in the high frequency region, most of the TE wave and the TM wave are less affected by the TEM wave, and the signal component mainly depends on the true discharge charge.

Considering the above-described attenuation characteristics of the TEM wave in the high frequency range and the range of the cut-off frequency of the TM wave, etc.
By targeting the frequency region above GHz, the combined component of the TE wave and the TM wave in the electromagnetic wave is maximized,
It is possible to detect a signal component due to substantially true discharge charge.

Returning to FIG. 1, the operation of the partial discharge detection device, particularly a specific procedure for detecting a partial discharge, will be described. FIG.
Is a spectrum analyzer 1 of the electromagnetic wave received by the antenna 15 when the partial discharge occurs inside the GIS.
FIG. 7 is a spectrum distribution diagram at 7. As described in the related art, the spectral component of the electromagnetic wave is affected by the shape and structure of the device, and resonates or anti-resonates depending on the value of the frequency, and appears as the intensity of the spectrum. Tend to decrease as the frequency increases, and as can be seen from FIG. 4, the spectral distribution in the frequency region of 1 GHz or more is less affected by differences in the structure of the device. This is considered to be a result of the fact that the signal component depending on the true discharge charge of the partial discharge occupies most in this frequency region as described with reference to FIGS.

First, the partial discharge is detected by generating a partial discharge of a known charge of 100 pc in a metal container using a gas insulated switchgear for testing, and transmitting an electromagnetic wave signal of the partial discharge received by the antenna 15 to the amplifier 16. After that, the frequency is analyzed by the spectrum analyzer 17. This result is shown in FIG. Here, the upper limit frequency of the analysis is 3
The reason why the frequency is set to GHz is that a general-purpose measuring instrument is used, and it is a matter of course that a higher frequency region may be included in the detection target. This data is sent to the arithmetic unit 18,
For example, the spectrum is integrated in a frequency range of 1.2 to 3.0 GHz and a spectrum integrated value is output. This data is stored in the storage device 19.

Next, this partial discharge detection device is attached to the gas insulated switchgear to be monitored for partial discharge, and power is applied. The spectrum is analyzed by the spectrum analyzer 17 in the same procedure as described above. The result is shown in FIG. And the arithmetic unit 1
At 8, a spectrum integral value is obtained and stored in the storage device 19. At the same time, data at the time of no charge is also collected (Fig. 5
(C)).

Now, the spectrum integrated value at the time of power application is -30d.
In Bm, it is assumed that the spectrum integration value at the time of no power application is −40 dBm, and when a significant difference is recognized in detection accuracy, it is determined that partial discharge has occurred. Also, assuming that the spectrum integration value when a partial discharge of a known charge amount (100 pC) shown in FIG. 5A is generated is -10 dBm, the monitored object shown in FIG. And -2
From 0 (−30 − (− 10)) dBm, the true discharge charge amount is calculated as 10 pC.

The reason why the spectrum integral value is calculated and this value is used to determine the occurrence of partial discharge or to detect the amount of charge generated by partial discharge is that the detection frequency is 1
By setting the frequency to GHz or more, the fluctuation due to the resonance depending on the structure of the device is suppressed, but since it is not zero, the influence of the fluctuation of the resonance frequency due to the device difference is reduced by calculating the integral value. This is to improve the detection accuracy.

As described above, in the first embodiment of the present invention, the detection frequency of the electromagnetic wave is set to 1 GHz or more at which the TM wave component is the maximum component. It becomes possible. In addition, since the determination is made based on the spectrum integrated value, the influence of the structural difference of the devices is further suppressed, and highly accurate detection is possible.

Embodiment 2 FIG. 5D shows the internal noise spectrum of the measuring instrument with respect to the noise spectrum at the time of no power application (FIG. 5C) in the apparatus described with reference to FIG. Comparison of the two spectra indicates that noise exists in a specific frequency region. This corresponds to a frequency band used for a broadcast wave, a mobile phone, a wireless device, or the like. If spectral integration is performed including these noises, the accuracy decreases.

In the second embodiment, based on a plurality of frequency domains excluding the frequency domain in which these extraneous noises may exist, for example, data shown in FIGS. 2-1.3 GHz, 1.6-1.8 GH
z, three frequency regions of 2.0 to 2.7 GHz are set, and for all cases to be compared, spectrum integration is performed for these frequency regions, and the sum of integrated values in the three regions is calculated to obtain the spectrum integration. Value. As a result, the influence of external noise can be minimized,
The accuracy of partial discharge detection is further improved.

Embodiment 3 In the third embodiment, a description will be given of a partial discharge detection device capable of suppressing the influence of a so-called external corona. That is, in the case of a structure in which the bushing 14 is provided as in the case of the gas insulated switchgear shown in FIG. 1, it is generated at a high voltage application portion exposed to the atmosphere, such as a terminal portion of the bushing 14 and a transmission line connected thereto. When the antenna 15 detects an electromagnetic wave generated by the external corona,
The electromagnetic wave signal due to the partial discharge generated inside the metal container 11 to be originally detected cannot be detected with high accuracy, and this measure is required.

FIG. 6 shows the waveform (a) of the partial discharge current pulse in SF ₆ gas and the current pulse waveform (b) of the air corona which is a partial discharge in the air. The former has a higher rising steepness of the current pulse. Therefore, when the spectrum analysis of both current pulses is performed, as shown in FIGS. 7A and 7B, the discharge current pulse (b) in the air becomes the partial discharge pulse (a) in the SF ₆ gas.
, There is little high frequency component, and most of the spectrum exists below 1 GHz, and at 1.2 GHz, the component decreases to 0 to 10%.

From the results of the above study, the frequency domain for which the arithmetic operation unit 18 calculates the spectral operation value is 1.2G.
When the frequency is set to Hz or more, the influence of the external air corona can be suppressed to a sufficiently low level, and the detection accuracy of the partial discharge generated inside the gas insulated switchgear is improved accordingly.

Embodiment 4 In the following embodiment,
A technique for determining a position where a partial discharge occurs in a gas-insulated electric device using the partial discharge detection device according to the present invention will be described. FIG. 8 is a sectional view showing a part of a gas-insulated switchgear as a gas-insulated electric device.
Reference numerals 11e to 11e denote unit metal containers, and insulating spacers 13a to 13d sandwiched between flange portions formed at respective ends.
Are articulated through. The conductors 12a to 12e are supported by the insulating spacers 13a to 13d. 20a to 20d are insulating spacers 13a to 13d
Is a partial discharge detection device installed on the outer periphery of the device.

FIG. 9 shows the internal configuration of the partial discharge detection device 20. In the figure, reference numeral 21 denotes an antenna which receives an electromagnetic wave generated by partial discharge inside the metal container 11 and leaking into the air via the insulating spacer 13. 22 is an antenna 21
, A high-pass filter that passes a frequency component of 1 GHz or more and blocks a frequency component lower than that, 23 denotes an amplifier that amplifies the output signal from the high-pass filter 22, and 24 denotes a function similar to the high-pass filter 22. And 25 is a high-pass filter 2
4 is a detector for detecting the output signal from 4, and 26 is a detector 25
The amplifier 27 amplifies the output signal from the amplifier 26. The display 27 uses a liquid crystal screen or the like to display the output signal from the amplifier 26. Although not shown, the partial discharge detection device 20 has a battery therein, is independently portable, and has a structure that can be easily attached to and detached from the outer periphery of the insulating spacer 13 by an attached detachable mechanism. .

Next, the operation, that is, the procedure for determining the partial discharge occurrence position will be described. As shown in FIG. 8, the partial discharge detection devices 20a to 20d are provided on the outer periphery of each of the insulating spacers 13a to 13d.
20d is installed, the output value of the electromagnetic wave signal at the time of power application is read from the display 27 of each partial discharge detection device 20, and the magnitude of the output value is compared. Now, as shown in FIG.
In the case where a partial discharge has occurred on the surface of the portion near the insulating spacer 13b of FIG. 3c, each partial discharge detection device 20a for detecting an electromagnetic wave signal by a true discharge charge generated therefrom
Due to the distance attenuation characteristics, the detected output values of ２０20d differ depending on the distance to the partial discharge occurrence position. In this example, the output value of the partial discharge detection device 20b becomes the maximum, and then becomes the order of 20c, 20a, and 20d. Therefore, in this example, the partial discharge detection device 20 having the largest detection value
It can be determined that a partial discharge has occurred inside the metal container 11c between b and the second partial discharge detection device 20c.

What is important here is that, by using a high-pass filter, an electromagnetic wave signal having a frequency of 1 GHz or more is to be detected. As a result, as described in the first to third embodiments, the detection is performed. The output is the structure of the device,
Since the detection output is almost independent of the shape, and the detection output changes almost faithfully according to the attenuation characteristic according to the distance from the partial discharge occurrence position, the position determination described in the fourth embodiment can be performed more accurately. It is done.

In FIG. 9, since the high-pass filter 22 is also inserted before the amplifier 23, even if a relatively strong signal in the frequency range of less than 1 GHz is output from the antenna 21, the high-pass filter 22 can be used. 2
2 can prevent such a problem that the amplifier 23 is saturated with the unnecessary signal in the low frequency range. When the output from the antenna 21 is weak, the input signal of the high-pass filter 24 inserted after the amplifier 23 increases due to the amplifying action of the amplifier 23, and exhibits a highly accurate filter function.

In FIG. 8, a plurality of partial discharge detectors 20 are prepared and attached to each of the insulating spacers 13 to detect them at the same time. However, the phenomenon of partial discharges remains the same within a certain period of time. Since it may be considered to be maintained, one partial discharge detection device 20 may be used to detect the mounting position while sequentially moving the mounting position.

Embodiment 5 FIG. FIG. 10 shows a modification of the partial discharge detection device. In this partial discharge detection device 20A, FIG.
, Band-pass filters 28 and 29 are used in place of the high-pass filters 22 and 24. The bandpass filters 28 and 29 allow the electromagnetic wave signal received by the antenna 21 to be in a frequency range of 1 GHz or more and free from external noise such as broadcast waves and mobile phones, for example, 2.0 to 2.0 GHz.
Only the electromagnetic wave signal in the range of 2.7 GHz is passed, and the position of the partial discharge is determined based on the detection signal of the frequency in this range. This enables more accurate position determination without being affected by the external noise.

Embodiment 6 FIG. FIG. 11 is a configuration diagram showing a partial discharge detection device according to Embodiment 6 of the present invention.
The basic configuration of the partial discharge detection is the same as that of the fourth and fifth embodiments, and thus the description thereof is omitted. Here, a part that improves the practicality of the detection work will be described below.

In the drawing, reference numeral 30 denotes a measuring vehicle, and 31 and 32 denote a signal processing device and a transmission control device mounted on the measuring vehicle 30. Reference numeral 33 denotes each of the partial discharge detection devices 20a to 20a.
Coaxial cables 34 and 35 connecting the output terminal of 20d and the signal processing device 31 are a telephone line and an antenna for transmitting and receiving signals to and from a control center or the like.

After installation of the gas insulated switchgear on site, at the end of internal inspection or at the time of periodic inspection, etc., it is required to confirm whether harmful partial discharge has occurred therein, and to determine the location of occurrence. However, in this embodiment, since the necessary equipment is mounted on the measurement vehicle 30 and is configured to be portable, this operation is extremely simple. That is, the measurement vehicle 30 is moved to the site, and the
If the necessary wiring is installed, the partial discharge can be immediately detected at the site, and the detection signal is transmitted via the telephone line 34 and the antenna 35, so that the detection can be continuously performed even in a remote control station. Monitoring becomes possible. In addition, if the transmission of each part is performed by digital signals,
The effect of noise during this period can be sufficiently suppressed.

Embodiment 7 FIG. FIG. 12 is a configuration diagram showing a partial discharge detection device according to Embodiment 7 of the present invention.
Here, an optical fiber is used for extracting a signal from each partial discharge detection device 20. That is, 36a to 36d are electro-optical signal converters provided at the output terminals of the respective partial discharge detectors 20a to 20d, 37 is a monitoring device, 38 is a photoelectric converter, 39 is a signal processor, and 40 is a transmission control unit. Device. Reference numeral 41 denotes an optical fiber that connects each of the electro-optical signal converters 36a to 36d and the opto-electric signal converter 38 of the monitoring device 37. Thereby, intrusion of noise at the detection site is reliably prevented, and it is possible to detect a partial discharge with high accuracy.

Embodiment 8 FIG. FIG. 13 is a configuration diagram showing a partial discharge detection device according to Embodiment 8 of the present invention.
In the figure, 42 is a bushing, 43 is a bushing accommodating section, 44 is a disconnector accommodating section, 45 is a circuit breaker accommodating section, 46 is a disconnector accommodating section, and 47 and 48 are busbar accommodating sections. 13a
Reference numerals 13e to 13e denote insulating spacers, and 20a to 20e denote partial discharge detection devices, all of which are the same as those described above. 49 is an internal electrode type partial discharge detection device attached to the bushing accommodating portion 43, provided with an internal electrode that outputs an intermediate potential between the high potential of the conductor and the ground potential of the metal container by the partial pressure of the capacitor, and A conventionally known partial discharge detection device for detecting a partial discharge from an output. Here, unlike the other partial discharge detection devices 20, a partial discharge generated at any location inside the device based on a detection signal in a frequency range of less than 1 GHz Is detected.

The internal electrode type partial discharge detector 49 detects a relatively low frequency electromagnetic wave signal. Therefore, since the above-described method of detecting a pulse caused by apparent discharge charge is used, there is a disadvantage that the apparatus is easily affected by the shape and structure of the apparatus. Relatively little attenuation. Paying attention to this latter characteristic, in the case of a part in the metal container of the gas insulated switchgear which occupies a large space, for example, in the one shown in FIG. As a monitoring procedure, the internal electrode type partial discharge detection device 49 is normally set in a detection operation state, and when this detects the occurrence of partial discharge, the detection signal is received and the partial discharge detection device described above is received. 20a-20
e to start a highly accurate partial discharge detection operation.

With the above configuration, there is an advantage that when there is a request to constantly monitor the partial discharge in the gas insulated switchgear, the content of the monitoring work is simplified and the cost is reduced.

In the partial discharge detector 20 described with reference to FIGS. 9 and 10, the detection output of the signal from the high-pass filter 24 or the band-pass filter 29 is displayed. And the magnitude of the partial discharge may be detected from this. In the above, the case where the present invention is applied to a gas insulated switchgear has been described. However, for example, the present invention can be similarly applied to other types of gas insulated electric devices including a transformer and a reactor, and has the same effect. Needless to say.

[0057]

As described above, the partial discharge detecting device for gas-insulated electrical equipment according to the first aspect of the present invention uses the detection frequency of the electromagnetic wave detecting means to change the detection frequency of the electromagnetic wave to the TM wave (the electric field travels in the traveling direction and the magnetic field travels in the traveling direction). Frequency component higher than the cut-off frequency of the partial discharge, the signal component that depends on the true discharge charge of the partial discharge will be detected, and it is hardly affected by the structure of the device. It is possible to detect partial discharge with no high accuracy.

Further, in the partial discharge detection device for gas-insulated electric equipment according to claim 2, the detection frequency of the electromagnetic wave detecting means is set to 1 GHz or more. Highly accurate detection of the partial discharge which is not affected is reliably realized.

A partial discharge detecting apparatus for a gas insulated electric device according to a third aspect of the present invention includes, as an electromagnetic wave detecting means, an antenna for receiving an electromagnetic wave and a spectrum analyzer for obtaining a spectrum distribution of an output from the antenna. The spectrum integrated value obtained by integrating the spectral components in the frequency domain is obtained when the partial discharge of the gas-insulated electrical equipment is detected and when no charge is applied or when the known charge is partially discharged. Or the detection of the amount of charges generated by the partial discharge is performed, so that a slight influence due to the difference in the structure of the device is eliminated, and the detection accuracy of the partial discharge is further improved.

The spectral integrated value of the partial discharge detection device for a gas-insulated electrical device according to the fourth aspect is an arithmetic operation of a value obtained by integrating spectral components in a plurality of predetermined frequency regions excluding a frequency region where external noise exists. Since the sum is used, the influence of external noise is removed, and the detection accuracy of the partial discharge is further improved.

According to a fifth aspect of the present invention, there is provided an apparatus for detecting partial discharge of a gas-insulated electric device, wherein an antenna for receiving an electromagnetic wave and a signal having a frequency equal to or higher than a predetermined frequency are inserted at an output side of the antenna. A high-pass filter and an amplifier inserted on the output side of the high-pass filter, and determine an output value from the amplifier when a partial discharge of the gas-insulated electric device is detected and when no charge is applied or when a known charge is partially discharged. Since the determination of the occurrence of partial discharge or the detection of the amount of charge generated by partial discharge is performed from the obtained output values, it is possible to detect a signal component depending on the true discharge charge of partial discharge, and the need for an amplifier is eliminated. Saturation operation can be avoided.

According to a sixth aspect of the present invention, there is provided a partial discharge detecting device for a gas-insulated electric device, wherein an electromagnetic wave detecting means excludes an antenna for receiving an electromagnetic wave and a frequency region inserted into an output side of the antenna and having external noise. A bandpass filter that allows a signal in a predetermined frequency range to pass therethrough, and an amplifier inserted on the output side of the bandpass filter,
The output value from the amplifier is determined when detecting partial discharge of the gas-insulated electrical device and when no power is applied or when a known amount of electric charge is partially discharged. Since the charge amount is detected, it is possible to detect the partial discharge with high accuracy without being affected by external noise, and to avoid unnecessary saturation operation of the amplifier.

According to a seventh aspect of the present invention, there is provided a partial discharge detection device for a gas-insulated electric device, wherein the unit body is housed in a container formed by connecting a plurality of unit containers via insulating spacers. The electromagnetic wave detecting means according to claim 1 is attached to an outer periphery of the insulating spacer,
Since the position of occurrence of partial discharge inside the gas-insulated electric device is determined from the relative comparison of the detection signals of the electromagnetic wave detection means in each of the insulating spacers, the partial discharge is hardly affected by the structure of the device and is performed with high accuracy. The position where the discharge occurs can be determined.

The partial discharge detection device for a gas-insulated electric device according to claim 8 is a device for detecting the difference between the high potential of the device main body and the ground potential of the container due to the partial pressure of a capacitor. An internal electrode that outputs an intermediate potential is provided,
An internal electrode type partial discharge detection device that detects a partial discharge generated inside the gas-insulated electric device based on a detection signal in a frequency region of less than 1 GHz of the output of the internal electrode; Since the partial discharge occurrence position is determined when the partial discharge is detected, the monitoring of the partial discharge can be performed simply and inexpensively.

Further, in the partial discharge detecting device for a gas insulated electric device according to the ninth aspect, the detection frequency of the electromagnetic wave detecting means is set to 1.2 GHz or more. The detection accuracy of the generated partial discharge is further improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a partial discharge detection device for a gas-insulated electric device according to Embodiment 1 of the present invention.

FIG. 2 is a diagram illustrating a model of a typical partial discharge.

FIG. 3 is a diagram illustrating each component of an electromagnetic wave due to partial discharge.

FIG. 4 is a diagram showing an actual measurement example of a spectrum distribution of electromagnetic waves due to partial discharge.

FIG. 5 is a diagram showing an example of actual measurement of a spectrum distribution under each detection condition when partial discharge is detected.

FIG. 6 is a diagram showing measured waveforms of partial discharge pulses in SF ₆ gas and in air.

FIG. 7 is a diagram showing a spectral distribution of a partial discharge pulse in SF ₆ gas and air.

FIG. 8 is a configuration diagram showing a partial discharge detection device of a gas-insulated electric device according to Embodiment 4 of the present invention.

9 is a diagram showing an internal configuration of the partial discharge detection device 20 of FIG.

FIG. 10 is a diagram showing an internal configuration of a partial discharge detection device 20A of a gas-insulated electric device according to Embodiment 5 of the present invention.

FIG. 11 is a configuration diagram illustrating a partial discharge detection device for a gas-insulated electric device according to a sixth embodiment of the present invention.

FIG. 12 is a configuration diagram showing a partial discharge detection device for a gas-insulated electric device according to a seventh embodiment of the present invention.

FIG. 13 is a configuration diagram illustrating a partial discharge detection device for a gas-insulated electric device according to an eighth embodiment of the present invention.

FIG. 14 is a configuration diagram showing a conventional partial discharge detection device for a gas-insulated electric device.

FIG. 15 is a diagram showing an actual measurement example of a spectrum distribution of an electromagnetic wave due to partial discharge obtained by the device of FIG.

[Explanation of symbols]

11, 11a to 11e Metal container, 12, 12a to 12
e conductor, 13, 13a to 13d insulating spacer, 15
Antenna, 16 amplifier, 17 spectrum analyzer, 18 arithmetic unit, 19 storage device, 20, 20a ~
20d partial discharge detection device, 21 antenna, 22, 2
4 High pass filter, 23 amplifier, 28, 29 Band pass filter, 49 Internal electrode type partial discharge detector.

──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Kiyoshi Inami 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Michiaki Matsuda 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric (56) References JP-A-6-235749 (JP, A) JP-A-9-121409 (JP, A) JP-A-3-259756 (JP, A) JP-A-7-231558 (JP, A) A) JP-A-11-271382 (JP, A) JP-A-11-223654 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 31/12 H02B 13/02 H02G 5 / 06 391

Claims (9)

(57) [Claims] 1. A gas-insulated electric device comprising means for detecting an electromagnetic wave generated inside a gas-insulated electric device, and detecting a partial discharge generated inside the gas-insulated electric device based on an output from the electromagnetic wave detection means. In the partial discharge detection device, the detection frequency of the electromagnetic wave detecting means is set to a frequency region higher than a cutoff frequency of a TM wave (a component in which an electric field travels in a direction perpendicular to the traveling direction) of the TM wave. A partial discharge detection device for gas-insulated electrical equipment, characterized in that: 2. The detection frequency of the electromagnetic wave detecting means is 1 GHz.
2. The partial discharge detection device for gas-insulated electrical equipment according to claim 1, wherein z is not less than z. 3. An apparatus for detecting electromagnetic waves, comprising: an antenna for receiving an electromagnetic wave; and a spectrum analyzer for obtaining a spectrum distribution of an output of the antenna. It is characterized in that it is determined at the time of partial discharge detection and at the time of no charge application or at the time of partial discharge of a known charge, and determination of the presence or absence of partial discharge occurrence or detection of the partial discharge generated charge amount is performed from the obtained integral values of both spectra. The partial discharge detection device for a gas-insulated electric device according to claim 2. 4. The gas insulation according to claim 3, wherein the spectral integrated value is an arithmetic sum of values obtained by integrating spectral components in a plurality of predetermined frequency regions excluding a frequency region in which external noise exists. Partial discharge detection device for electrical equipment. 5. An electromagnetic wave detecting means comprising: an antenna for receiving an electromagnetic wave; a high-pass filter inserted at an output side of the antenna and passing a signal of a predetermined frequency or higher; and an amplifier inserted at an output side of the high-pass filter. ,
The output value from the amplifier is determined when detecting partial discharge of the gas-insulated electrical device and when no power is applied or when a known amount of electric charge is partially discharged. 3. The partial discharge detection device for gas-insulated electrical equipment according to claim 2, wherein the detection of the amount of charge is performed. 6. An antenna for detecting electromagnetic waves, a band-pass filter inserted into an output side of the antenna and passing a signal in a predetermined frequency region excluding a frequency region where external noise is present, and the band-pass filter as the electromagnetic wave detecting means. And an amplifier inserted into the output side of the gas-insulated electrical device.The output value of the amplifier is determined when partial discharge of the gas-insulated electrical device is detected and when no charge is applied or when a known amount of charge is partially discharged. 3. The partial discharge detection device for gas-insulated electrical equipment according to claim 2, wherein the determination of the occurrence of partial discharge or the detection of the amount of charge generated by partial discharge is performed based on the value. 7. A gas-insulated electrical device in which a plurality of unit containers are connected to each other via an insulating spacer and the device main body is housed in a container.
Wherein the partial discharge occurrence position inside the gas insulated electric device is determined from a relative comparison of detection signals of the electromagnetic wave detection means in the insulating spacers. Partial discharge detector for gas insulated electrical equipment. 8. An internal electrode for outputting an intermediate potential between a high potential of the device main body and a ground potential of the container by a partial pressure of a capacitor in a part of a container of the gas insulated electric device. An internal electrode type partial discharge detection device for detecting a partial discharge generated inside the gas-insulated electric device based on a detection signal in a frequency range of less than 1 GHz; A partial discharge detection device for a gas insulated electric device, wherein the partial discharge occurrence position according to claim 7 is determined. 9. The detection frequency of the electromagnetic wave detection means is set to 1.2
9. The partial discharge detection device for gas-insulated electrical equipment according to claim 7, wherein the frequency is set to GHz or higher.