JP3172626B2 - Partial discharge detection method for high voltage 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 method for diagnosing insulation of a high-voltage device in a high-voltage power receiving facility, and more particularly to a method for detecting partial discharge for insulation diagnosis.

[0002]

2. Description of the Related Art As a conventional method of detecting partial discharge for insulation diagnosis of internal high-voltage equipment in a high-voltage power receiving facility, a traveling wave current accompanying partial discharge of a high-voltage equipment is subjected to a waveform by a current transformer (CT) installed in a cable section. At the same time, a coupling capacitor is installed between each phase on the bus side and the ground, and a current waveform of each phase and three phases flowing through the coupling capacitor is detected.
When the phase difference between the current flowing through the three-phase batch portion of the coupling capacitor and the current flowing through the cable portion is 180 degrees, there is a method of detecting that partial discharge has occurred. In general, the insulation diagnosis of the high-voltage power receiving equipment is performed by stopping the power transmission and measuring the insulation resistance. Further, there is a method of detecting a high-frequency component of a zero-phase current of a high-voltage pull-in cable, and determining the magnitude and spectrum pattern of the high-frequency component.

[0003]

As described above, the conventional partial discharge detection method for insulation diagnosis of the internal high-voltage equipment of the high-voltage power receiving equipment is based on the premise that monitoring is always performed. Need to be attached to Further, since the current waveform is detected and it is determined whether or not the discharge is partial discharge based on the phase difference, when the external noise component is large, the waveform is buried in the noise, so that it is difficult to detect the phase difference. Further, the discharge includes an inter-earth discharge and an inter-phase discharge, and the discharge waveform of the partial discharge does not always have a phase difference of 180 degrees. Further, in the method of measuring the insulation resistance while stopping the power transmission, the insulation resistance between the phases cannot be measured, so that the insulation deterioration between the phases cannot be detected.

In the method of measuring the high-frequency component of the zero-phase current, when noise from the power supply side and the load side of the high-voltage power receiving equipment frequently occurs, the noise is partially detected only with the magnitude of the high-frequency component and the spectrum pattern. There is a possibility that it is erroneously determined that the discharge has occurred.

The present invention has been made in view of the above points, and a novel partial discharge that can easily and reliably measure a partial discharge generated in a high-voltage device inside a high-voltage power receiving facility in an operating state. It is intended to provide a detection method.

[0006]

According to the present invention, in a high-voltage power receiving facility in an operating state, a partial discharge generated from a high-voltage device is measured by measuring a high-frequency component of a zero-phase current of a high-voltage lead-in cable, thereby reducing a portion of the high-voltage device. When judging the presence or absence of discharge , 1 MHz to 9 M
Hz signal bandwidth and spectral pattern
Measured based on its size and spectral pattern.
A partial discharge detection device for high-voltage equipment, wherein the presence or absence of partial discharge is determined . Further, the partial discharge detection method for detecting a high frequency component of the zero-phase current of the high-voltage cable entry partial discharges generated from the high pressure equipment of the high pressure power receiving equipment during operation, and the high frequency component
And the magnitude of the signal in the frequency band of 1 MHz to 9 MHz
And the spectral pattern and measure their size and spec.
The presence or absence of partial discharge in high-voltage equipment based on the
With a constant, partial discharge detection device of the high-pressure equipment, which comprises defended by measuring the noise and the frequency and duration of the power source side and the load side portion and a high-pressure power receiving equipment generated from the high-pressure equipment It is.

[0007]

[Function] A split type high-frequency current sensor is installed in a cable that leads to a high-voltage device inside a high-voltage power receiving facility, and the presence or absence of partial discharge of the high-voltage device can be determined by measuring the high-frequency component of the zero-phase current. . As the high frequency component, 1
The magnitude of the signal in the frequency band of MHz to 9 MHz is measured, and the presence or absence of the partial discharge of the high-voltage device can be reliably measured based on the magnitude. In the high-voltage power receiving equipment during operation, the partial discharge generated by the high-voltage equipment is measured for the high-frequency component of the zero-phase current of the high-voltage lead-in cable, the level fluctuation of the high-frequency component is detected, and the partial discharge is determined based on the frequency and duration of the occurrence. Erroneous determination of occurrence of a partial discharge is prevented by reliably discriminating the noise from the noise.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for detecting partial discharge of a high-voltage device according to the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a partial discharge detection method for a high-voltage device according to an embodiment. That is, it is connected to the transformer 5 in the high-voltage power receiving equipment 4 so that power is transmitted through the switch-in or the like by the lead-in cable 3. High-frequency sensor 1
And 1 MHz to 9 of signals from the high-frequency sensor 1
Measuring instrument 2 for measuring the level of the frequency component in the MHz band
Is provided.

FIG. 6 shows an example of a measuring circuit for a unit test of an instrumentation transformer (PT). That is, a high-frequency sensor 8 is provided on the ground wire 7 of the secondary winding of the instrument transformer 6, and a signal from the sensor 8 is detected by the measuring device 9. The current transformer (C
FIG. 7 shows an example of a measurement circuit for the unit test T). Similar to the above-described instrument transformer, the secondary side ground wire 11 of the current transformer 10 is used.
Is provided with a high-frequency sensor 12, and a signal from the sensor 12 is detected by a measuring device 13.

FIGS. 2 and 3 are graphs showing an example of the result of measuring the high frequency component of the partial discharge of the instrument transformer (PT) and the current transformer (CT) by the measurement circuit. (A), (B), and (C) each have a range of 1,
The output waveform when changing to 10,100 MHz is shown. From these figures, the high frequency component of the partial discharge is 10 MHz.
It can be seen that the attenuation occurs above z.

FIGS. 4 (A), 4 (B) and 4 (C) show examples of the measurement results of the frequency components of the noise of the actual high-voltage power receiving equipment. Similarly, output waveforms when the range is changed to 1, 10, and 100 MHz are shown in (A), (B), and (C), respectively. The frequency components below 1 MHz are large and attenuated in the frequency band above 1 MHz.

Further, when a deterioration instrument transformer (PT) in which a partial discharge of about 1000 pC is generated is mounted on a high-voltage power receiving facility, the high-frequency component measured at the lead-in cable 3 is converted into noise of the actual high-voltage power receiving facility. FIG. 5 shows a comparison with the frequency component. From this figure 1M
In the band of Hz to 9 MHz, the high frequency component of the partial discharge is detected to be about 20 dB larger than the frequency component of the noise.

From the above results, according to the method for measuring partial discharge according to the method of the present invention, the presence or absence of the occurrence of partial discharge is reliably determined by measuring the magnitude of the frequency component in the frequency band of 1 MHz to 9 MHz. can do.

[0014] Next, an embodiment of the present invention defined in claim 2, wherein FIG. 8
A description will be given with reference to FIG. In FIG. 8 showing a configuration example of the partial discharge detection device, a high-frequency sensor 1 is attached to the lead-in cable 3, and a frequency component in a band of 1 MHz to 9 MHz in a signal from the high-frequency sensor 1.
Level signal is input to the partial discharge detection device 20.
The partial discharge detection device 20 splits the signal from the high-frequency sensor 1 into three by a splitter 21 that splits the signal.
From the spectrum pattern / level detector 22,
The signals are input to the pulse level detector 23 and the pulse number detector 24, respectively. The spectrum pattern / level detector 22 detects a spectrum pattern and a level in a predetermined partial discharge detection frequency band for a predetermined time. The pulse level detector 23 detects a pulse level in a predetermined partial discharge detection frequency band for a predetermined time. Further, the pulse number detector 24 counts the number of pulses in a predetermined partial discharge detection frequency band for a predetermined time. Then, these measurement results are output to the arithmetic processing unit 25, respectively.

The arithmetic processing unit 25 includes the detectors 2
2, 23 and 24 are controlled, and a detection signal and a detection result are input as input data. Further, the arithmetic processing unit 25 performs the operation shown in the flowchart of FIG. That is, the input data is respectively accumulated (step S1), and after a predetermined time elapses (step S2), the stable part of both the pulse number of the accumulated data and the pulse level data is determined. If there is no stable portion, each signal is detected again for a predetermined time and determined (step S3). After a lapse of a predetermined time, the low-order stable part of the pulse number and pulse level data is detected from the accumulated data. At this time, if there is no lower stable portion, the determination is performed again (step S4). If there is a lower stable portion, the occurrence of partial discharge is determined based on the spectrum pattern and level (step S5). Further, when both data are not stable, the occurrence of the partial discharge is determined based on the spectrum pattern and the level when the pulse level is stable (step S6). If there is no stable part (step S7), it is determined that there is noise and determination is impossible (step S8).

The above series of operations is performed to prevent erroneous determination of the high-frequency spectrum pattern and level due to single noise.

[0017]

As described above, according to the method for detecting partial discharge of a high-voltage device of the present invention, a partial discharge of a high-voltage device in a high-voltage power receiving facility in an operating state is detected by attaching a high-frequency sensor to a lead-in cable portion. The determination can be made in a short time without adding any equipment just by detecting the level of the component. In addition, a high-frequency sensor is attached to the cable that draws in the partial discharge of the high-voltage equipment in the high-voltage power receiving equipment in operation, measures the high-frequency component of the zero-phase current, detects the level fluctuation of the high-frequency component, and determines the frequency and duration. By discriminating the partial discharge from the noise, it is possible to reliably determine the occurrence of the partial discharge based on the spectrum and level of the high-frequency component of the zero-phase current.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a method for detecting partial discharge of a high-voltage device in a high-voltage power receiving facility according to an embodiment of the present invention;

FIG. 2 is a graph showing an example of a measurement result of a high frequency component of a partial discharge of a PT alone, where (A) is 1 MHz and (B) is 10 MHz.
MHz, (C) is in the range of 100MHz,

FIG. 3 is a graph showing an example of a measurement result of a high frequency component of a partial discharge of a single CT, where (A) is 1 MHz and (B) is 10 MHz;
MHz, (C) is in the range of 100MHz,

FIG. 4 is a graph showing an example of a measurement result of a frequency component of noise of an actual high-voltage power receiving equipment, wherein (A) is in a range of 1 MHz, (B) is in a range of 10 MHz, (C) is in a range of 100 MHz,

FIG. 5 is a graph showing an example of a measurement result when a deteriorated PT is attached.

FIG. 6 is a measurement circuit diagram of FIG. 2;

7 is a measurement circuit diagram of FIG. 3,

FIG. 8 is a configuration diagram of a partial discharge detection device applied to a partial discharge detection method of a high-voltage device according to another embodiment;

FIG. 9 is a flowchart for explaining the operation of the partial discharge detection device of FIG. 8;

[Explanation of symbols]

 1,8,12 High-frequency sensor 2,9,13 Measuring device 3 Drop-in cable 4 High-voltage power receiving equipment 5 Transformer 6 Instrument transformer (PT) 7,11 Ground wire 10 Current transformer (CT) 20 Partial discharge detection device 21 Demultiplexer 22 Spectrum pattern / level detector 23 Pulse level detector 24 Pulse number detector 25 Arithmetic processing unit

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuo Kotani 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture “Inside Power System Research Laboratories, Hitachi, Ltd.” (72) Inventor Kenichiro Soma Hitachi City, Ibaraki Prefecture 5-1-1 Hidakacho “Inside Power System Research Laboratories, Hitachi Cable, Ltd.” Examiner Atsushi Ozaki (56) References JP-A-5-209921 (JP, A) JP-A-5-45400 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01R 31/12

Claims (2)

(57) [Claims] In a high-voltage power receiving facility in an operating state,
High voltage pull-in cable for partial discharge generated from high voltage equipment
By measuring the high-frequency component of the zero-phase current of the
When determining the presence or absence of partial discharge of the vessel, the high-frequency component
The magnitude of the signal in the frequency band of 1 MHz to 9 MHz
And the spectral pattern, and measure its size and
Judgment of partial discharge based on spectrum pattern
A method for detecting partial discharge of high-voltage equipment, characterized in that : 2. A high-voltage device of a high-voltage power receiving facility during operation.
Phase discharge of high voltage cable with partial discharge generated from
In the partial discharge detection method of detecting the high-frequency component of the flow,
As the high frequency component, a frequency band of 1 MHz to 9 MHz
Measure the magnitude and spectral pattern of the signal in the
Based on its size and spectral pattern,
In addition to determining the presence or absence, partial discharge generated from high-voltage equipment
And noise from the power supply and load side of the high-voltage power receiving equipment.
Discrimination by measuring the frequency and duration of
And a method for detecting partial discharge of a high-pressure machine.