JP3126392B2 - Partial discharge detector for gas insulated switchgear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detecting device used for detecting a partial discharge generated inside a gas insulated switchgear, and more particularly to a single-phase device and a three-phase collective device. And a partial discharge detection device for a gas insulated switchgear.

(Prior Art) In recent years, there has been a need to reinforce the substation equipment due to soaring land and an increase in power supply in urban areas. A so-called gas-insulated switchgear, in which substation equipment such as a circuit breaker and a circuit breaker are housed and arranged in a closed container, and which has a compact installation resistance per kV.A and environmental resistance, is widely used.

The gas insulated switchgear as described above has advantages such as downsizing and elimination of the exposed charging portion of the grounding tank, but has difficulty in maintenance diagnosis due to high performance and increases maintenance and repair work time. There is a drawback that when an abnormality occurs inside the container, the reliability is significantly reduced.

Therefore, conventionally, in order to improve the reliability of the entire gas insulated switchgear, an appropriate design and design of the device have been proposed.
Although efforts have been made to manufacture the device, it is necessary to confirm and monitor the reliability of the entire device as part of improving the quality of the power supply capability, and various effective means have been studied.

As one of such means, there is a partial discharge detector used for detecting a partial discharge generated inside the gas insulated switchgear. FIG. 6 shows an example of a conventional partial discharge detector. That is, a general closed gas switch is housed in a metal container 1, which is electrically divided by an insulating spacer 2 and connected in the longitudinal direction. In the metal container 1, a central conductor 3, which is a high-voltage charging unit electrically connected to a transmission line (not shown), is supported by the insulating spacer 2. The metal container 1 is grounded by a ground wire (not shown). The insulating spacer 2 is provided with an electrode 4 for detecting electric power. A stray capacitance C2 exists between the electrode 4 and the metal container 1, and the stray capacitance C2 is shown as a capacitor 5. . And
A partial discharge detection unit 7 is connected to both terminals of the capacitor 5 via a signal lead-in line 6. The partial discharge detecting section 7 is configured by connecting an amplifier circuit 9 to a filter 8 for extracting a signal of a specific frequency, and further connected to a peak detector and an integrating circuit 10. A power supply 11 is connected to these devices.

[0008] The conventional partial discharge detector thus constructed operates as described below. That is, the center conductor 3
When a high voltage is applied to the capacitor 5, the stray capacitance C1 existing between the center conductor 3 and the electrode 4 and the capacitor 5 constitute a voltage divider, and a shared voltage is generated at both ends of the capacitor 5. When a partial discharge pulse (corona pulse) is generated in the switch, the high frequency component (signal) resulting from the discharge is superimposed on the shared voltage and input to the partial discharge detection unit 7. In the partial discharge detecting section 7, a signal of a specific frequency corresponding to the partial discharge pulse is extracted by the filter 8, amplified by the amplifier circuit 9, and then output to the outside via the peak detector and the integrating circuit 10. Then, from this output signal, it is possible to detect that partial discharge has occurred inside the switch.

[0009]

However, the conventional partial discharge detector as described above has the following problems to be solved.

First, the conventional partial discharge detector detects a signal of a specific frequency corresponding to a partial discharge pulse at a predetermined timing, and then integrates and outputs an arbitrary time width. Cannot be determined. However, the generation form of the partial discharge pulse generated due to the abnormality on the main unit side is closely related to the main circuit voltage waveform (phase) depending on the type of each abnormality as shown in FIG. 7 as an example. On the other hand, in many cases, external noise that becomes an obstacle at the time of measuring partial discharge occurs randomly regardless of the main circuit voltage phase. For this reason, even if a signal of a specific frequency is simply extracted from the partial discharge detector as in the related art, there is a possibility that external noise may be included in the signal, and it is difficult to perform highly accurate partial discharge detection. there were. Also,
Even if only the presence or absence of a signal of a specific frequency is detected irrespective of the main circuit voltage phase, it is impossible to know the relationship between the phase and the discharge pulse as shown in FIG. It was impossible.

In particular, in the three-phase batch type equipment section of the gas insulated switchgear, the voltage waveform induced by the commercial voltage is normally balanced in three phases, and even if the partial discharge itself is detected, the main circuit voltage waveform Because you can not know
It was not possible to know the cause of the partial discharge based on the phenomenon as shown in FIG. The present invention has been made in view of the above prior art, and has as its object to detect a highly accurate partial discharge pulse without being affected by external noise, and to provide a single-phase device for a gas insulated switchgear. It is an object of the present invention to provide a partial discharge detection device capable of investigating the cause of the occurrence of the partial discharge not only in the unit but also in the three-phase batch type device unit in which the commercial frequency voltage is balanced.

[Structure of the Invention]

[0013]

In order to achieve the above-mentioned object, the present invention provides a single-phase high-voltage charging section accommodated in a grounded metal container filled with an insulating gas while the charging section is supported by an insulating spacer. Part of a gas-insulated switchgear having a single-phase equipment part made up of the above and a three-phase collective-type equipment part also housed in a grounded metal container while supporting three-phase high-voltage charging parts supported by insulating spacers. In the discharge detection device, the following means are combined.

(1) Provided in the insulating spacer portion of the single-phase device portion or the grounded metal container in a state insulated from the grounded metal container, and detects both the partial discharge signal and the commercial frequency signal of the single-phase device portion. Floating electrode on the single-phase device side.

(2) A partial-discharge detecting section on the single-phase equipment section side which is connected to the floating electrode on the single-phase equipment section side and separates and detects a partial discharge signal from both the partial discharge signal and the commercial frequency signal.

(3) A three-phase unit for detecting a partial discharge signal of the three-phase package type device, which is provided in the insulating spacer portion of the three-phase package type device unit or the grounded metal container so as to be insulated from the ground metal container. Floating electrode on the side of the collective device.

(4) A partial-discharge detection unit connected to the floating electrode of the three-phase collective device for detecting the partial discharge signal.

(5) The commercial frequency signal is connected to the floating electrode on the single-phase device side and separates the commercial frequency signal from both the partial discharge signal and the commercial frequency signal on the single-phase device side. A main circuit voltage phase detector that detects a phase signal.

(6) The partial-discharge detecting section and the main
The partial discharge signal output from the circuit voltage phase detector and the main
Based on the circuit voltage phase signal,
Measures the partial discharge and the three-phase batch type equipment
The split discharge detector and the main circuit voltage phase detector on the single-phase device side
From the partial discharge signal and the main circuit voltage phase signal
The partial discharge of an arbitrary phase in the three-phase batch type equipment
Arithmetic unit to perform.

[0020]

According to the present invention having the above-described structure, in the single-phase device, the partial discharge signal and the commercial frequency signal are detected from the same floating electrode, and the main circuit voltage phase generated from the commercial frequency signal is detected. By measuring the partial discharge at an arbitrary phase based on the reference pulse corresponding to the signal, it is possible to distinguish between the external noise and the partial discharge pulse, and in what pattern the partial discharge occurs with respect to the main circuit voltage phase. You can know if it has occurred.

On the other hand, the three-phase collective device detects partial discharge of an arbitrary phase based on a reference pulse corresponding to the main circuit voltage phase signal detected in the single-phase device. As a result, it is possible to detect partial discharge of an arbitrary phase of the three-phase collective device, which was considered impossible in the past, and also in the three-phase collective device, it is possible to distinguish external noise from partial discharge pulses. In addition to this, it is possible to know in what pattern the partial discharge occurs with respect to the main circuit voltage phase.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be specifically described below with reference to FIGS.

FIG. 1 is a block diagram showing an outline of the apparatus of this embodiment. In FIG. 1, a single-phase device part A and a three-phase collective device part B constituting a gas insulated switchgear are housed in a grounded metal container 1, respectively. The grounded metal container 1 is electrically divided by an insulating spacer 2 and connected in the longitudinal direction. In the metal container 1, a central conductor 3, which is a high-voltage charging unit electrically connected to a transmission line (not shown), is supported by the insulating spacer 2. In this case, the single-phase device portion A supports a single-phase conductor 3, and the three-phase collective device portion B supports three-phase conductors.

A floating electrode 4 for detecting partial discharge is provided on the insulating spacer 2 on the side of the single-phase device section A. A floating capacitance C 2 exists between the floating electrode 4 and the metal container 1. The stray capacitance C2 is shown as capacitor 5. Both terminals of the capacitor 5 are connected to a detection section 7a on the single-phase device section A side via a signal drop line 6. The detection section 7a on the single-phase device section A side is composed of a partial discharge detection section and a main circuit voltage phase detection section, and a signal is obtained from the same floating electrode 4.

On the other hand, a floating electrode 4 for detecting partial discharge is provided on the insulating spacer 2 on the side of the three-phase collective device section B, and a floating capacitance C 4 exists between the floating electrode 4 and the metal container 1. The stray capacitance C4 is shown as a capacitor 5. To both terminals of the capacitor 5, a detection unit 7 a on the three-phase collective device unit B side is connected via a signal lead-in line 6. The detection unit 7a on the three-phase collective device unit B side is configured by a partial discharge detection unit that detects a partial discharge from a signal obtained by the floating electrode 4.

The detectors 7a and 7a on the single-phase device side and the three-phase batch type device side are connected to the receivers 7b and 3b on the single-phase device side.
It is connected to the receiving section 7b on the side of the collective phase type device section. Further, the detection unit 7a on the single-phase device side is also connected to the reception unit 7b on the three-phase batch type device unit side, and is detected by the main circuit voltage phase detection unit provided on the detection unit 7a on the single-phase device unit side. The received main circuit voltage phase signal is received by the receiving unit 7 on the three-phase batch type device unit side.
a is also input.

Next, the details of each of the detecting unit 7a and the receiving unit 7b will be described with reference to FIG.

First, a partial discharge detection section is provided on both the detection section 7a on the single-phase device section side and the detection section 7a on the three-phase batch type device section side. The partial discharge detection unit is connected to a transformer 12 for separating a high-frequency signal component from a signal detected by the floating electrode 4 and sending the signal component to a subsequent electronic circuit unit. A bandpass filter 13 is provided for extracting a signal in a specific frequency band corresponding to a pulse (possibly including a partial discharge pulse and noise). The band-pass filter 13 is connected to an amplifier 14 and a detection circuit 15 for processing the signal of the specific frequency, and an integration circuit or a peak hold circuit 16 for converting the signal of the specific frequency to a predetermined pulse width. Further, the integration circuit or the peak hold circuit 16 includes
A V / F conversion circuit 17 for modulating the pulse signal of a specific frequency obtained as described above, an E / O conversion circuit 18 for converting the modulated signal into an optical signal, and a single-phase device for converting the optical signal Alternatively, an optical fiber 19 for transmitting the signal to the receiving unit 7b on the three-phase batch type device unit side is provided.

On the other hand, the detection section 7a on the single-phase equipment section side is provided with a main circuit voltage phase detection section. The main circuit voltage phase detection unit, like the partial discharge detection unit, includes a transformer 12 for separating a high-frequency signal component from a signal detected by the floating electrode 4 and sending the separated high-frequency signal component to a subsequent-stage electronic circuit unit. And a band pass filter 20 connected to the filter 12 for extracting only the commercial frequency from the high frequency signal. The bandpass filter 20 is connected to an amplifier 21, a comparator 22 for detecting a specific phase of the commercial frequency as a pulse, and a pulse shaping circuit 23 for shaping the detected pulse. Further, the pulse shaping circuit 23 includes a V / F conversion circuit 17 for modulating the voltage phase pulse signal obtained by the pulse shaping circuit 23, similarly to the partial discharge detection unit, and converts the modulated signal into an optical signal. An E / O conversion circuit 18 for conversion and an optical fiber 19 for transmitting the optical signal to the receiving section 7b on the single-phase device section side and the three-phase collective device section side are provided. In the drawing, reference numeral 31 denotes a converter for converting the supplied power to an arbitrary voltage.

The O / E section for converting a signal of a specific frequency sent from the partial discharge detecting section of each detecting section 7a into an electric signal is provided to the receiving sections 7b on the single-phase apparatus side and the three-phase collective apparatus side. 24
And an F / V conversion circuit 25 are provided.
These circuits are connected via an amplifier 26 to an integrating circuit 27, A /
It is connected to a D conversion unit 28 and an arithmetic unit 29. Also, each receiving unit 7b includes an O / E unit 24 and an F / V conversion circuit for converting a voltage phase pulse signal from a main circuit voltage phase detecting unit of the detecting unit 7a on the single-phase device unit side into an electric signal. 2
5 are provided, and these circuits are connected to a calculator 29 via an amplifier 26 and a waveform shaping circuit 30. Based on the partial discharge signal and the main circuit voltage phase signal output from the partial discharge detection unit and the main circuit voltage phase detection unit, these computing units 29 determine the arbitrary phase for the single-phase device unit and the three-phase batch-type device unit. Is used to measure the partial discharge of.

The partial discharge detecting device according to the present embodiment having such a configuration operates as follows.

When a partial discharge occurs in the single-phase equipment section A of the gas-insulated switchgear, a high-frequency signal including all frequency components is superimposed on the commercial frequency as shown in FIG. You. This signal is supplied to a band-pass filter 13.2 provided in the detection unit 7a.
At 0, it is separated into a signal of a specific frequency including a partial discharge pulse and a commercial frequency. Of these, the signal of a specific frequency that may include the partial discharge pulse and its noise is measured in real time, and is amplified and detected by the amplifier 14 and the detection circuit 15.
After the detection, the integration circuit or the peak hold circuit 16
Time width that can be measured by phase resolution, for example, 1 in 1 cycle
The signal is peak-held at 0 to 1/100 or less, then modulated by the V / F converter 17, output as an optical signal by the E / O converter 18, and sent to the receiver 7 b through the optical fiber 19. On the other hand, the commercial frequency detected by the band-pass filter 20 is amplified by the amplifier 21, and then a specific phase, for example, the phase of the zero-cross point is detected as a voltage phase pulse by the comparator 22. The waveform is shaped by the shaping circuit 23. After that, the voltage phase pulse is modulated by the V / F conversion circuit 17, output as an optical signal by the E / O conversion circuit 18, and sent to the receiving unit 7 b through the optical fiber 19. The pulse of the specific frequency including the partial discharge pulse thus optically transmitted and the voltage phase pulse are respectively supplied to the O / E unit 24 and the F / V conversion circuit 2 in the receiving unit 7b.
5. The operational unit 29 is converted from the optical signal during transmission by the amplifier 26.
Is converted back into an electric signal that can be processed.

The detection of partial discharge by the calculator 29 from both pulse signals obtained as described above is performed as follows. First, the pulse of the specific frequency including the partial discharge pulse is supplied to the integrating circuit 27 of the receiving unit 7b in FIG.
It is shaped into a rectangular wave pulse as shown by. On the other hand, based on the voltage phase pulse output from the waveform shaping circuit 30 (in FIG. 4, the voltage phase pulse P1 is output at the zero cross point for a fixed time t1), the arithmetic unit 29 measures the measurement timing pulse P1.
2 is output. The measurement timing pulse P2 is calculated by the calculator 29 in a measurement start time t1 and a measurement time width t2.
Are output in a range where the partial discharge pulse is most likely to be generated among the phases of the main circuit voltage when viewed from the partial discharge pulse generation pattern of FIG. The A / D converter 28 converts the pulse signal of the specific frequency including the partial discharge pulse into a digital value only while the measurement timing pulse P2 is being output, and outputs the signal from the A / D converter 28. , It is determined whether or not a pulse signal of a specific frequency exists in the phase portion, in other words, whether or not a partial discharge has occurred.

That is, the band-pass filter 1 of the detection unit 7a
The signal of the specific frequency separated by the step 3 includes noise that is an obstacle in measuring the partial discharge. Even if the signal is converted into a constant pulse signal by the peak hold circuit 16 or the like, the included noise is Not removed. However, performing the A / D conversion of the pulse signal of the specific frequency only during the output of the measurement timing pulse P2 as described above requires a portion where the partial discharge pulse of the main circuit voltage phase is most likely to be generated, that is, noise and noise. Indicates that a pulse of a specific frequency exists in a phase part that is difficult to imagine. As a result, the probability that the pulse of this specific frequency can be determined as a partial discharge pulse is extremely high, and a conventional partial discharge detector that determines partial discharge only by the presence or absence of a pulse of a specific frequency corresponding to the partial discharge pulse The detection accuracy of the partial discharge is remarkably improved as compared with the above.

Since the generation pattern of the partial discharge pulse with respect to the main circuit voltage phase has the characteristics shown in FIG. 7, the measurement timing can be changed by appropriately changing the measurement start time t1 and the measurement time width t2. If the pulse P2 is output to the expected partial discharge occurrence range of a specific pattern and the presence or absence of the pulse of the specific frequency in that portion is detected,
It is possible to determine in what pattern the partial discharge pulse is generated, and to determine the cause of the partial discharge.

On the other hand, in the three-phase collective device section B, similarly to the single-phase device section A, a detection signal is sent to the receiving section 7a via the floating electrode 4 and the detecting section 7a. in this case,
In the three-phase batch type device section B, since the three-phase voltage waveform induced by the commercial voltage is balanced, only the partial discharge signal is input to the detection section 7a as shown in FIG. Therefore,
In the receiving unit 7b, the partial discharge signal and the main circuit voltage phase pulse from the detecting unit 7a of the single-phase device unit A are processed by the computing unit 29, so that, similar to the single-phase device unit A, Partial discharge can be detected and its cause can be determined.

As described above, in this embodiment,
A signal of a specific frequency including a partial discharge signal is detected from the same floating electrode embedded in the insulating spacer portion of both the single-phase device portion A and the three-phase collective device portion B. The commercial frequency signal is detected from the floating electrode embedded in the unit, and based on the reference pulse corresponding to the main circuit voltage phase created from this commercial frequency signal, not only in the single-phase device unit but also in the three-phase batch type device unit By measuring the partial discharge at an arbitrary phase, the phase of the partial discharge can be analyzed, and a highly accurate and more reliable partial discharge detector can be provided.

[0038]

As described above, according to the present invention, a partial discharge signal and a commercial frequency signal are detected from the same floating electrode provided in an insulated state in an insulating spacer portion of a single-phase device or a grounded metal container. Highly accurate partial discharge detection that can measure the partial discharge of an arbitrary phase based on the reference pulse corresponding to the main circuit voltage phase created from the commercial frequency signal and has high detection accuracy and can identify the cause of the partial discharge An apparatus can be provided. In particular, according to the present invention, the reference pulse corresponding to the main circuit voltage phase detected by the single-phase device,
By outputting the data to the three-phase batch type device, a highly reliable partial discharge detection device that can detect the partial discharge and can detect the cause of the partial discharge in the three-phase batch type device as well as the single-phase device Can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a partial discharge detection device according to the present invention.

FIG. 2 is a circuit diagram showing details of a detection unit and a reception unit in the embodiment of FIG.

FIG. 3 is a graph showing input and output waveforms of a detection unit of a single-phase device according to the present invention.

FIG. 4 is a graph showing a relationship between a main circuit voltage phase of a single-phase device and each detection pulse in the present invention.

FIG. 5 is a graph showing input and output waveforms of a detection unit of the three-phase collective device unit according to the present invention.

FIG. 6 is a circuit diagram illustrating an example of a conventional partial discharge detector.

FIG. 7 is a graph showing a partial discharge generation cause and a partial discharge pulse generation pattern. A: Single-phase equipment part B: Three-phase collective equipment part 1: Metal container 2: Insulating spacer 3: Center conductor 4: Floating electrode 5: Capacitor 6: Signal drop-in wire 7: Partial discharge detector 7a: Detection unit 7b: Receiver 8 Filter 9 Amplifier circuit 10 Peak detector and integrating circuit 11 Power supply 12 Transformer 13 Bandpass filter 14 Amplifier 15 Detection circuit 16 Integration circuit or peak hold circuit 17 V / F conversion Circuit 18 E / O conversion circuit 19 Optical fiber 20 Bandpass filter 21 Amplifier 22 Comparator 23 Pulse shaping circuit 24 O / E conversion circuit 25 F / V conversion circuit 26 Amplifier 27 Integration circuit 28 A / D converter 29: arithmetic unit 30: waveform shaping circuit 31: converter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-15670 (JP, A) JP-A-55-55269 (JP, A) JP-A-62-19774 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G01R 31/12 H02B 13/065

Claims (1)

(57) [Claims] 1. A grounded metal container filled with an insulating gas,
A single-phase equipment part containing a single-phase high-voltage charging part supported by insulating spacers, and a three-phase high-voltage charging part also stored in a grounded metal container with the insulating spacers supporting it. A partial-discharge detection device for a gas-insulated switchgear having a three-phase batch-type device unit comprising: a single-phase device unit; A single-phase device side floating electrode for detecting both the partial discharge signal and the commercial frequency signal of the phase device portion, and both the partial discharge signal and the commercial frequency signal connected to the single-phase device side floating electrode A partial-discharge detecting unit for separating and detecting a partial-discharge signal from the single-phase device unit; Partial discharge signal of phase batch type equipment A floating electrode on the side of the three-phase batch-type device for detecting the partial discharge detector connected to the floating electrode on the side of the three-phase batch-type device for detecting the partial discharge signal; A main circuit connected to the floating electrode on the phase device side, separating the commercial frequency signal from both the partial discharge signal and the commercial frequency signal on the single phase device side, and detecting a main circuit voltage phase signal from the commercial frequency signal Voltage phase detector , partial discharge detector on the single-phase device side, and main circuit voltage phase detector
And the partial discharge signal and main circuit voltage phase signal output from
Measures partial-discharge of single-phase equipment based on arbitrary phase
In addition, the single-phase with the partial discharge detector on the 3-phase
Output from the main circuit voltage phase detector on the device side
3-phase batch type based on discharge signal and main circuit voltage phase signal
A partial discharge detection device for a gas insulated switchgear , comprising: a calculation unit for measuring a partial discharge of an arbitrary phase of a device unit.