JPH07107627A - Partial discharge detector for switchgear - Google Patents

Abstract

PURPOSE:To enhance sensitivity in the detection of a faint partial discharge. CONSTITUTION:A pulse current is fed from a high frequency current transformer to a band-pass filter 3 through a matching resistor 1 and an amplifier 2. The band-pass filter captures only the frequency components of partial discharge pulse which is fed to a peak detecting circuit 4 where the peak values are held before being averaged through an averaging circuit 5 at a time width of several hundreds mS.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detecting device for detecting partial discharge such as corona discharge generated in a switchgear or the like.

[0002]

2. Description of the Related Art In FIG. 15 showing a conventional metal-closed switchgear with a partial discharge detector attached, a partition 51f is vertically provided at the rear of a metal box 51 surrounded by a mild steel plate. ing. A spacer 52 is provided on the ceiling portion at the rear of the upper end of the partition 51f, and the lower end of the conductor penetrating the axial center of the spacer 52 is connected to the upper end of a power receiving conductor 53A.

The lower end of the conductor 53A is curved in a U shape, and the end of the conductor 53B is substantially L-shaped with the lower end of the conductor 53B penetrating a pair of current transformers 54 attached to the rear surface of the partition 51f.
The top of 53D is connected. Of these, the upper conductor 53B
Is connected to the lower pole of the vacuum circuit breaker 55 housed in the circuit breaker chamber 51b, the lower pole of the conductor 53C is connected to the upper pole of the vacuum circuit breaker 55, and the upper edge of the conductor 53C is connected to the box 51 of the box 51. It is connected to a bus bar 56 arranged on the lower surface of the ceiling portion in a direction orthogonal to the plane of the drawing.

On the other hand, an instrument transformer room 51d provided under the circuit breaker chamber 51b accommodates an instrument transformer 57, and the primary side of the instrument transformer 57 is connected to the lower end of the conductor 53D. It is connected. Further, a lightning arrester chamber 51e provided under the instrument transformer room 51d houses a lightning arrester 58, and this lightning arrester 58 has one side of a conductor 51g supported by a partition 51f via an insulator (not shown). The other side of the conductor 51g is connected to the lower end of the conductor 53D.

Further, a ground bus bar is provided at the rear of the lower end of the box 51.
59 is provided in the direction orthogonal to the paper surface, one side of the ground conductor 60 is connected to the ground bus 59, and the other end of the ground conductor 60 is
It is connected to the ground rod of the metal box 51. A high-frequency current transformer (hereinafter, referred to as high-frequency CT) is loosely fitted in the ground conductor 60 in advance, and the coaxial cord wire on the secondary side of the high-frequency CT is attached.
62 is connected to a detection device (not shown). Further, an AE sensor 63 is attached to the upper end of the front surface of the instrument transformation chamber 51d, and a coaxial cord wire 64 on the output side of the AE sensor 63 is also connected to an ultrasonic detecting device (not shown).

In the metal-closed switchgear configured as described above, as a result of long-term operation, a transformer for an instrument is generated.
57 When the insulators and insulators that make up the vacuum circuit breaker 55 and the vacuum circuit breaker deteriorate, and dust adheres to the surface of the conductor, a partial discharge occurs between the metal tube and the phase of the ground potential,
As ultrasonic waves are generated, a pulse current due to partial discharge flows through the ground bus 59 and is discharged from the ground conductor 60 to the ground via the ground rod.

Therefore, in this metal-closed switchgear, the discharge current discharged to the ground by the high frequency CT is detected in the low frequency region of several 100 kHz of the pulse current, and is input to the amplifier circuit of the detector (not shown). There is. In addition, the detection method by this high frequency CT is
It is also shown in the official gazette. On the other hand, the AE sensor 63 detects an ultrasonic wave of several tens of kHz due to partial discharge, converts the ultrasonic wave into an electric signal, and inputs the electric signal to the amplification circuit of the detection device via the coaxial cord 64.

[0008]

However, noise may be mixed in the pulse current and ultrasonic waves detected by the metal-closed switchgear. As the noise mixed in the pulse current, the pulse voltage of the harmonic component that enters the power supply system to which the metal closed switch gear is connected and intrudes, and the metal closed switch gear and the metal closed switch gear There are surge voltage generated by opening and closing the vacuum switch housed in the closed metal switchgear and voltage of harmonic component of the power receiving transformer.

On the other hand, in the noise detected by the AE sensor, the vibration of the metal component due to the electromagnetic force generated by the current flowing through the conductor of the metal-closed switchgear or the metal-closed switchgear is installed in the vicinity of the noise. Also, there are ultrasonic waves generated by the discharge of electric equipment and ultrasonic waves generated from a wireless communication device.

When noise enters the high-frequency CT or AE sensor in this way, the detection accuracy of the partial discharge decreases, so
In order to reduce the influence of noise, the frequency band is selected and the noise removal circuit is used together. However, if the pulse current flowing through the ground line is detected in the low frequency region of several 100 kHz, the detection accuracy of partial discharge can be improved by synchronizing with the measurement circuit, but it is not the frequency corresponding to the rise time of partial discharge. , The pulse current accompanying partial discharge cannot be detected.

Therefore, the noise invading the measuring circuit cannot be removed by the method of amplifying and detecting the partial discharge pulse current on the measuring circuit. Therefore, the partial discharge pulse and noise flowing through the ground line are simultaneously input to the measuring circuit and tuned to several hundred kHz. On the other hand, although ultrasonic waves detect several tens of kHz, noise of partial discharge is detected, so that noise easily enters and the detection accuracy decreases.

Therefore, in the conventional partial discharge detection apparatus in which the detection accuracy is lowered by the intrusion of noise, the partial discharge cannot be detected at the early stage of the insulation deterioration in which the partial discharge charge amount is weak, and the insulation deterioration is caused. Partial discharges cannot be detected until the later stage of deterioration that has progressed. Further, the detected discharge charge amount is also the maximum value, and not all are captured. As is well known, since insulation deterioration depends on discharge energy due to partial discharge, in order to judge the depth of insulation deterioration, it is necessary to grasp two factors, that is, the amount of individual discharge charge and the frequency of occurrence.

Therefore, an object of the present invention is to obtain a partial discharge detection device capable of detecting a weak partial discharge with high accuracy regardless of the presence or absence of noise.

[0014]

According to a first aspect of the present invention, there is provided a partial discharge detecting device for detecting a partial discharge generated in a switch gear by penetrating a ground wire through a high frequency current transformer attached to the switch gear. The pulse signal of the partial discharge detected by the high frequency current transformer is peak-detected through a bandpass filter, and the peak-detected pulse signal is averaged.

Further, the invention according to claim 2 is a high frequency current transformer in a partial discharge detecting device for detecting a partial discharge generated in a switch gear by penetrating a ground wire into a high frequency current transformer attached to a switch gear. The pulse signal of the partial discharge detected by the detector is peak-detected through a band pass filter of several MHz to several tens of MHz, and the peak-detected pulse signal is averaged over a time width of several hundred ms. .

Further, according to a third aspect of the invention, in the partial discharge detecting device for detecting the partial discharge generated in the switchgear by penetrating the ground wire through the high frequency current transformer attached to the switchgear, the high frequency current transformer is provided. The pulse signal of the partial discharge detected by the detector is peak-detected through a bandpass filter in the frequency band from 1.5 MHz to 40 MHz, and the peak-detected pulse signal is averaged over a time width of about 330 ms. Partial discharge detector.

According to a fourth aspect of the present invention, there is provided a high frequency current transformer in a partial discharge detecting device for detecting a partial discharge generated in the switch gear by penetrating a ground wire through a high frequency current transformer attached to the switch gear. The partial discharge pulse signal detected by the detector is peak-detected through a bandpass filter in the frequency band of 1.5 MHz to 40 MHz, and the peak-detected pulse signal is connected to a waveform detector.

Further, the invention according to claim 5 is a high frequency current transformer in a partial discharge device for detecting a partial discharge generated in a switch gear by penetrating a ground wire through a high frequency current transformer attached to a switch gear. A light emitting diode is connected to the secondary side of, and an optical fiber is connected to this light emitting diode.

[0019]

According to the invention described in claims 1, 2, 3 and 4, the pulse current generated by the partial discharge inside the switchgear differs depending on the aspect of the discharge, but is generated by the void inside the insulator. It is several ns to several tens of ns, and it is several ns to several tens of ns when it is generated on the surface of an insulator or in the air. By filtering only the pulse current of this frequency component, the pulse current of partial discharge can be accurately captured, and the peak value and the frequency of occurrence of these pulse currents are averaged in the time width of several 100 ms. By that,
It is possible to capture the discharge energy within a fixed time. This makes it possible to efficiently detect discharge energy that causes insulation deterioration.

Further, since the frequency band is limited to the noise that is suddenly generated, the ratio of superposition on the pulse current is reduced, and the averaging process is performed within a fixed time. The peak value is reduced and the detection accuracy of the partial discharge is improved. In the invention according to claim 5, the partial discharge is detected by lighting the light emitting diode.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the partial discharge detection device of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a partial discharge detection device of the present invention. Point A is the same as in FIG.
It is connected to the output terminal of a high-frequency CT having a frequency characteristic of several MHz to several tens of MHz, which is formed by a ferrite core and penetrates the ground wire.

A partial discharge pulse current is input to this point A, and is output to the input side of the non-inductive matching resistor 1 connected by the coaxial cord line. The pulse current output from the matching resistor 1 is amplified by the amplifier 2 of several tens of dB and then input to the bandpass filter 3 adapted to the frequency component of the pulse current. The output side of this bandpass filter 3 has a terminal B
And the peak detection circuit 4, the peak detection circuit 4 holds the peak of the pulse current with a time constant of several ms, and passes through the averaging processing circuit 5 that performs averaging processing with a time width of several 100 ms. After being amplified by the amplifier 6 of several to several tens of dB, DC4mA to 20mA via the voltage-current conversion circuit 7.
Is output from the terminal C.

FIG. 2 shows an oscillographic waveform of the output voltage of the high-frequency current transformer input to the point A, in which the pulse corresponding to a steep partial discharge with a rise time of several to several tens of ns becomes the first wave. Is appearing. After that, the pulse due to the vibration of the first wave is superimposed at a frequency lower by about one digit, and the frequency of several 100 kHz appears due to the vibration of the measurement system and is attenuated.

That is, a pulse wave in which three kinds of frequency components of several tens MHz to several hundreds kHz are superimposed is input to the point A. Of these, the hand-pass filter 3 having the frequency band shown in FIG. 3 is provided in order to extract the frequency component corresponding to the partial discharge. In Fig. 3, the frequency with a fluctuation range of 10 dB ranges from about 1.5 MHz to about 40 MHz.
The frequency component of the pulse current due to partial discharge obtained by the inventors through experiments is about 3 MHz for air discharge and creeping discharge, and about 30 MHz for void discharge inside insulators such as instrument transformers. . Therefore, the pulse current due to the partial discharge passes through the bandpass filter 3, and the frequency components that are different due to the superimposed vibration component and external noise are suppressed. The pulse current that has passed through the bandpass filter 3 is output as the original waveform of the partial discharge at the point B, and is also input to the peak detection circuit 4. In the peak detection circuit 4, the peak is held with a time constant of about 1 ms, and individual pulse currents are similarly peak-detected. After that, the averaging processing circuit 5 performs the averaging processing in a time width of about 330 ms. In other words, the peak detected pulse current is about 33
The magnitude and frequency are accumulated in a time width of 0 ms and then divided by the frequency of the pulse current to obtain an average value. This is because when measuring pulse current based on 50 Hz, if peak detection is performed with a time constant of 1 ms, the pulse current will be decomposed into 20 per cycle, and the peak value of decomposed discharge and the total number of occurrence frequencies will be almost measured. You can also make these about 330 ms 1
This is because if 6.5 cycles are averaged, it is possible to catch the partial discharge that occurs continuously. Even when noise or the like that occurs suddenly enters, the peak value is reduced by averaging.

The averaged signal is output by the amplifier 6 by several d.
After amplifying from B to several tens of dB, 4 to 20 by voltage-current conversion circuit
It is converted into a direct current of mA and input from a point C to a computer (not shown), and the partial discharge is constantly monitored. FIG. 4 is a characteristic diagram showing the relationship between the current value at point C and the discharge charge of partial discharge.
The output characteristics vary depending on the frequency of power transmission. Line a shows that the frequency n of occurrence of partial discharge per second is 50 <n <10.
0, the line b indicates the discharge current output from the point c when 100 <n <200, and the line c indicates 1000 <n <2000.

By performing the averaging process in this way, the discharge current varies depending on the generation frequency even if the discharge charge amount is the same. That is, the rate of insulation deterioration is determined by the magnitude of the discharge energy, but in the partial discharge detection device of the present invention, the higher the frequency of discharge occurrence, that is, the greater the discharge energy, the greater the output current. Therefore, it is possible to detect the partial discharge that causes the insulation deterioration with high sensitivity.

On the contrary, with respect to sudden noise and the like, the output current is reduced and suppressed because the frequency of occurrence is low even if the peak value is large. In the above embodiment, the time width of the pulse current to be averaged is set to about 330 ms, and 16.5 cycles are averaged. However, it may be increased depending on the capacity of the computer.

If a synchroscope or the like is connected at point B in FIG. 1 and the partial discharge pulse is observed in comparison with that in FIG. 5, the location of the discharge can be estimated, and it can be promptly checked during a regular inspection. Can respond. FIG. 5 shows the relationship between a typical partial discharge pulse and the phase of the voltage applied to the part when this partial discharge occurs. In FIG. 5, the voltage V
In contrast to the waveform of (a), since (a) is a pulse generated on the negative polarity of the voltage phase, it can be determined to be an air discharge from a conductor or the like, and (b)
Can be determined to be void discharge inside the insulator due to the phase having a large voltage steepness, and discharge due to contact failure at the conductor connecting portion, for example, because (c) is near the voltage zero point.

As described above, the high frequency CT can be attached to the ground bus of the switch gear to detect the partial discharge generated from the entire switch gear. However, even for individual devices, for example, as shown in FIG. In the current transformer, the high frequency CT17 can be passed through one side of the terminal 16 connected to the secondary winding 15 to detect the partial discharge.

In FIG. 6, a secondary winding 15 and an iron core 19 are formed so as to intersect with the primary winding 18, and these are fixed by an insulating layer 20 cast with an insulating resin. In addition, high frequency CT17
The output of is connected to terminal 21, which connects the coaxial lead. A pad 22 is embedded in the lower end of the connection layer 20, fixed to a pedestal 24 by a bolt 23, and further fixed to a frame 25 of a box body of the switch gear. In the current transformer for an instrument thus configured, since the partial discharge due to the deterioration of the primary winding 18 and the insulating layer 20 almost flows into the secondary winding 15, the pulse current due to the partial discharge can be detected. .

Next, FIG. 7 shows an example in which a high frequency CT is installed in the high voltage portion. High frequency CT17 penetrates through the conductor 26,
The light emitting diode 8 is connected to the secondary terminal of the high frequency CT17, one side of the optical fiber 9 is connected to the light emitting diode 8 and the other side (not shown) performs optical conversion to take out an electric signal by partial discharge. In FIG. 7, a conductor to which a high voltage is applied
Reference numeral 26 is fixed to the box body by a support insulator 10 and a connecting fitting 11, and a shield 13 is fixed to a conductor 26 in the high-frequency CT 17 and the secondary winding 12 for relaxing an electric field.

As described above, the light emitting diode 28 normally does not operate due to the simple structure in which the pulse current appearing at the secondary terminal of the high frequency CT17 is directly converted into light, and light is emitted when the pulse current due to partial discharge flows. Therefore, the partial discharge can be detected. In addition, the insulation of the signal line is
29 can handle.

In order to increase the detection sensitivity of these partial discharges, as shown in FIG. 8, by connecting a plurality of high-frequency CT17s in parallel and outputting them to the terminal D, the pulse current can be increased and the discharge energy can be increased. it can. As a result, the ratio of the output current to the discharged charge amount increases, and the detection sensitivity of partial discharge can be increased. The high-frequency CT 17 penetrates each of the ground lines 14, and the ground line 14 is connected to the ground pole of the switch gear 27. If a plurality of outputs of the high frequency CT17 are connected in series, the value of the pulse current increases and the detection sensitivity also increases.

Further, by attaching the high frequency CT to the switchgear or the whole ground wire and the ground wire of each device and detecting the partial discharge, the device in which the partial discharge has occurred can be specified.

Next, another embodiment of the partial discharge detection device of the present invention will be described. FIG. 9 is a block diagram showing another embodiment of the partial discharge detection device of the present invention. Of the sound wave and the pulse current generated by the occurrence of partial discharge inside the switchgear shown in FIG. 16, the sound wave propagates in the air and
Partial discharge is detected by the E sensor 63. AE sensor
The output of 63 is filtered by a narrow band filter 31 of about 27 kHz in FIG. 9, then amplified by the next preamplifier 32, further filtered by a filter 34, amplified by a main amplifier 34, and digitally by an A / D converter 35. It is converted into a signal and input to the AND circuit 42.

On the other hand, the pulse current flows through the box body of the switch gear, and flows from the ground bus 59 shown in FIG. 16 to the ground via the ground conductor 60. At this time, the output of the high frequency CT61 is as shown in FIG.
After being filtered by the filter 36, the peak detection circuit 37 performs peak detection, the averaging processing circuit 38 performs averaging processing, the amplifier 39 amplifies the signal, and the A / D converter 40 converts it to a digital signal. Input to the circuit 41.

FIG. 10 shows an AE sensor and an A / D of high frequency CT.
The outputs of the converters 35 and 40 and the output of the AND circuit 41 are shown. X
Section is the output of the AE sensor only, so the AND circuit 35
Is judged to be a sound wave other than partial discharge and is not output. The Y section is an output of only the high frequency CT circuit, and AND
The circuit 40 judges that it is noise and does not output it. Z part is A
Since both the E sensor and the high frequency CT circuit are outputting, the AND circuit 41 judges that it is a partial discharge signal and outputs it.

That is, the high frequency CT is output instantaneously, and A
Since the E sensor outputs after the propagation time of the sound wave, partial discharge occurs if the E sensors simultaneously output after the time difference t. Generally, in switch gears, the distance from the source of partial discharge to the AE sensor mounting part is about 1 m, so the propagation speed of air is about 30 m.
At 0 m / s, this time t is about 3 ms. Therefore, it is possible to easily prevent malfunction of the partial discharge detection device due to sound waves and noise other than partial discharge.

FIG. 11 is a block diagram in which the output signals of the high frequency CT are added. According to the experiment using the switch gear of the inventors, the output waveform of the high frequency CT shows that the first wave of the partial discharge has a frequency of about 4 MKz as described above with reference to FIG. 2, and then the frequency of about 200 kHz to be tuned in the measurement system. There is. Therefore, the discharge pulse current due to partial discharge is about 4 kHz.
And there is a frequency of 200 kHz.

Therefore, the output of the high frequency CT is 4 MHz and 20
Filtering is performed by bandpass filters 42A and 42B of 0 KHz, peak detection is performed by peak detection circuits 43A and 43B, averaging processing is performed by the next averaging processing circuits 44A and 44B, and further amplified by amplifiers 45A and 45B. / D converter 46A, 46
Convert to digital signal at B and add each signal by adder
Add at 47 and output.

On the broken lines L and M in FIG. 12, 4 MHZ and 200 kH
Output waveforms of A / D converters 46A and 46B of z circuit and adder
47 shows the output waveform. The output of the adder 47 shown by the broken line N is
Since the outputs of the 4MHz and 200kHz circuits are added, the output is amplified. Therefore, a weak partial discharge signal can also be detected.

When the box body constituting the switchgear has a large number of surfaces, the high-frequency CT is attached to the ground electrode of the power receiving panel by providing the high-frequency CT to prevent partial discharge occurring inside the entire power receiving equipment. All can be easily detected. That is, the main circuit conductors are lined up from the power receiving board to the feeder board, but the ground busbars are similarly connected, and the power receiving board is connected to the ground electrode. Therefore, if the high frequency CT 61 is provided on the ground wire 60 of the power receiving board, the partial discharge of the entire power receiving equipment can be detected.

In FIG. 13, the ground wire 54a of the secondary winding of the instrument current transformer 54 mounted on the partition plate 2 is penetrated through the high frequency CT 61A mounted on the partition plate 51f and connected to the ground bus 59. Indicates when.

According to the experiments by the inventors, the current transformer 54 for an instrument is
Most of the partial discharge pulse due to the internal abnormality is detected by the ground wire 54a of the secondary winding of the current transformer 54 for an instrument, and is not detected by the mounting base or the like. Therefore, by penetrating the high frequency CT 61A with the ground wire 54a of the secondary winding of the instrument current transformer 54, the abnormality of the instrument current transformer 54 can be detected early.

In FIG. 14, the grounding conductor 60 is attached to the high-frequency CT61 so as to penetrate, and the high-frequency CT61A is connected to a current transformer for an instrument.
This is a case where the secondary side winding ground wire 54a is attached to 62. By connecting the two high-frequency CTs 61 and 61A individually and as a whole, it is possible to detect the partial discharge and specify the storage device at the same time.

Further, even if a high frequency CT is used for the gas insulated switchgear, the electric motor and the transformer, the partial discharge can be detected in the same manner. Among them, in the gas-insulated device, the seeding speed of the AE sensor becomes slow, so the delay time may be set according to the density of the insulating gas. Also, in the transformer, it may be adjusted according to the propagation speed of oil.

[0047]

As described above, according to the invention of claim 1,
In a partial discharge detection device that detects the partial discharge generated in the switchgear by penetrating the ground wire through the high frequency current transformer attached to the switchgear, a bandpass filter for the partial discharge pulse signal detected by the high frequency current transformer By detecting the peak after passing through the pulse signal and averaging the pulse signal detected by this peak, the pulse wave was captured as the discharge energy within a certain period of time. It is possible to obtain a partial discharge detection device capable of detecting.

According to the second aspect of the present invention, in the partial discharge detecting device for detecting the partial discharge generated in the switch gear by penetrating the ground wire through the high frequency current transformer attached to the switch gear, The peak signal of the partial discharge pulse signal detected by the current transformer is detected through a band pass filter of several tens of MHz to several tens of MHz, and the peak detected pulse signal is averaged over a time width of several hundred ms. Since the partial discharge pulse is captured as the discharge energy in several 100 ms, it is possible to obtain the partial discharge detection device capable of detecting the weak partial discharge with high accuracy regardless of the presence or absence of noise.

According to the third aspect of the invention, in the partial discharge detecting device for detecting the partial discharge generated in the switch gear by penetrating the ground wire through the high frequency current transformer attached to the switch gear, The pulse signal of the partial discharge detected by the current detector is peak-detected through a bandpass filter in the frequency band of 1.5 MHz to 40 MHz, and the peak-detected pulse signal is averaged over a time width of about 330 ms. Since the partial discharge pulse is captured as the discharge energy in about 330 ms, it is possible to obtain the partial discharge detection device capable of detecting the weak partial discharge with high accuracy regardless of the presence or absence of noise.

Further, according to the invention described in claim 4, in the partial discharge detecting device for detecting the partial discharge generated in the switch gear by penetrating the ground wire through the high frequency current transformer attached to the switch gear, The partial discharge pulse signal detected by the current transformer is peak-detected through a bandpass filter in the frequency band of 1.5 MHz to 40 MHz, and this peak-detected pulse signal is connected to a waveform detection device. Since it is possible to discriminate the mode of the discharge part by the phase of, it is possible to obtain the partial discharge detection device capable of specifying the discharge part with a weak discharge pulse.

Further, according to the invention of claim 5,
In a partial discharge device that detects the partial discharge generated in the switchgear by penetrating the ground wire through the high frequency current transformer attached to the switchgear, connect the light emitting diode to the secondary side of the high frequency current transformer, Since the presence or absence of partial discharge can be determined by connecting the optical fiber to the presence or absence of lighting of the light emitting diode, it is possible to obtain a partial discharge detection device capable of detecting partial discharge with a simple configuration.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a partial discharge detection device according to claims 1, 2, 3 and 4.

FIG. 2 is a diagram showing output characteristics of the high frequency current transformer used in the present invention.

FIG. 3 is a graph showing frequency characteristics of a bandpass filter used in the present invention.

FIG. 4 is a graph showing the output characteristics of the partial discharge detection device of the present invention.

FIG. 5 is a graph showing the operation of the partial discharge detection device of the present invention.

FIG. 6 is a vertical cross-sectional view showing an application example of the partial discharge detection device of the present invention.

FIG. 7 is a diagram showing an embodiment of the partial discharge detection device according to claim 5;

FIG. 8 is a diagram showing another embodiment of the partial discharge detection device of the present invention.

FIG. 9 is a block diagram showing another embodiment of the partial discharge detection device of the present invention.

FIG. 10 is a diagram showing the operation of another embodiment of the partial discharge detection device of the present invention.

FIG. 11 is a block diagram showing still another embodiment of the partial discharge detection device of the present invention.

FIG. 12 is a diagram showing an output waveform after AD conversion of still another embodiment of the partial discharge detection device of the present invention.

FIG. 13 is a diagram showing still another embodiment of the partial discharge detection device of the present invention.

FIG. 14 is a diagram showing still another embodiment of the partial discharge detection device of the present invention.

FIG. 15 is a diagram showing an example of a metal closed switchgear to which a conventional partial discharge detection device is attached.

[Explanation of symbols]

1 ... Matching resistance, 2, 6 ... Amplifier, 3 ... Band pass filter, 4 ... Peak detection circuit, 5 ... Averaging processing circuit, 7 ... Voltage-current conversion circuit, 8 ... Light emitting diode, 9 ... Optical fiber, 10 ... Support insulator, 11 ... Connection fitting, 12, 15 ... Secondary winding, 13 ... Shield, 14 ... Ground wire, 16 ... Terminal, 17 ... High frequency current transformer, 18 ... Primary winding, 19 ... Iron core, 20 ... Insulation layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Ishikawa No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation Fuchu factory

Claims (5)

[Claims] 1. A partial discharge detection device for detecting a partial discharge generated in the switchgear by penetrating a ground wire through a high frequency current transformer attached to a switchgear, wherein the part detected by the high frequency current transformer A partial discharge detecting apparatus, wherein a pulse signal of discharge is peak-detected through a bandpass filter, and the peak-detected pulse signal is averaged. 2. A partial discharge detecting device for detecting a partial discharge generated in the switchgear by penetrating a ground wire through a high frequency current transformer attached to a switchgear, wherein the partial part detected by the high frequency current transformer The peak signal of the pulse signal of the discharge is passed through a band pass filter of several tens to several tens of MHz, and the peak signal is detected by several hundreds.
A partial discharge detection device characterized by performing averaging processing in a time width of ms. 3. A partial discharge detecting device for detecting a partial discharge generated in the switchgear by penetrating a ground wire through a high frequency current transformer attached to a switchgear, wherein the part detected by the high frequency current transformer. Discharge pulse signal 1.
A partial discharge detection device characterized in that peaks are detected through a band-pass filter in the frequency band of 5 MHz to 40 MHz, and the peak-detected pulse signals are averaged over a time width of about 330 ms. 4. A partial discharge detection device for detecting a partial discharge generated in the switchgear by penetrating a ground wire through a high frequency current transformer attached to a switchgear, wherein the part detected by the high frequency current transformer Discharge pulse signal 1.
A partial discharge detection device characterized in that peak detection is performed through a bandpass filter in the frequency band of 5 MHz to 40 MHz, and the peak signal thus detected is connected to a waveform detection device. 5. A partial discharge device for detecting a partial discharge generated in the switch gear by penetrating a ground wire through a high frequency current transformer attached to the switch gear, wherein a light emitting diode is provided on a secondary side of the high frequency current transformer. And a light emitting diode connected to an optical fiber.