JPS627310A - Preventive diagnosis of gas insulated switchgear - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a preventive diagnostic method for gas insulated switchgear.

In particular, it relates to a method suitable for automatically detecting the cause of abnormality occurrence.

[Background of the invention]

As a conventional method for preventive diagnosis of gas-insulated switchgear, e.g.
Partial discharge detection involves placing an electromagnetic coupling probe in close contact with an arbitrary position on the outer wall of a gas-insulated switchgear, amplifying the pulse signal generated during discharge using a pulse amplifier, and displaying this on the indicator. A device is known. With this method, it is possible to detect the occurrence of an abnormality, but it is not possible to detect the cause of the abnormality. Also, since it is monitored with an indicator, automatic detection is not possible. Ta.

[Purpose of the invention]

An object of the present invention is to provide a preventive diagnosis method that automatically detects both an abnormality and the cause of the abnormality in a gas-insulated switchgear without providing an additional mechanism inside the gas-insulated switchgear.

[Summary of the invention]

The present invention utilizes the fact that the cause of an abnormality in a gas-insulated switchgear is determined in relation to the partial discharge occurrence pattern.

By dividing one cycle of the main circuit voltage into several time periods and counting the partial discharge pulses that occur during the divided time periods, the partial discharge generation pattern can be confirmed, and gas-insulated switchgear automatically detects the occurrence of an abnormality and the cause of the abnormality.

[Embodiments of the invention]

Typical examples of the present invention will be shown below.

In FIG. 1, the gas insulated switchgear has a high voltage main circuit conductor 1, a disconnector 2. A voltage transformer 3 is housed in a case 4, and is insulated by gas filled in the case. When an abnormality occurs in the gas insulated switchgear and a partial discharge occurs in the case 4, a discharge current flows through the grounding wire 5 to the ground.

In the present invention, in order to detect this partial discharge, the main circuit voltage related thereto is first detected. The voltage transformer secondary voltage 18 stepped down by the voltage transformer 3 is applied to the square wave converter 9 and converted into a square wave 19, which is applied to one input terminal of the AND gate 81. Clock pulses are always applied to the other end of the AND gate 81 at a constant period from the clock source 10.

While the output is being issued to the square wave converter 9, the clock pulse passes through the AND gate At, passes through the OR gate 16e, and is applied to the counter 11, which operates to count the passed clock pulses, and after further counting, the counted value is written into the register 14 and stored. The above explanation is for positive waves.

In the case of a negative wave, the output of the square wave converter 9 is connected to the gate 17.
and the output of the NOT gate 17 is applied to the AND gate 82.
In addition to one input terminal of 82, the other terminal of 82 has a clock source 1.
Add an output of 0. As in the case of a positive wave, the output of the AND gate 82 is applied to the counter 11 via the OR gate 16 to count the passing clock pulses, and after counting, this counted value is written in the register 14. I'm here.

Here, the frequency of the clock source 10 is 8 times that of the alternating voltage.
Selected twice. On the other hand, a discharge current is input from a current transformer 6 installed on the ground wire 5. The output of 6 is applied to one input terminal of the AND gate 83 via the amplifier 7, and the pulse wave 20 which is the output of the counter 11 is given to the other terminal of the AND gate 83, so that the time of one pulse is A counter 12 counts the number of partial discharge pulses passing through the band. Write this count value to V sister 13.
Signals 18, 19, and 20 of each section have waveforms shown in FIG. 2, respectively.

The outputs of registers 13 and 14 and the output pulse 20 of counter 11 are input to computer 15.

The calculator 15 calculates the force '1 of the register 14 as shown in FIG.
The occurrence of an abnormality and the cause of the abnormality are detected by determining the air discharge pattern shown in FIG.

That is, in FIG. 3, first, in step s1, it is determined whether or not it is time to take in data based on the presence or absence of a data take-in request flag. If it is not the time to take in the data, it is placed in a standby state, and if yes, the contents of the V-sister 14 are read in step S2. This register 140 count value indicates which time period the sine wave of one cycle is divided into several time periods. The value of register 13 is loaded in step S3.

In step S4, at each time period determined by the register 140 count value, whether or not a count value is stored in the register 13 is sequentially detected over one cycle of the AC voltage, and the register 140 count value and the count value of the register 13 are sequentially detected. Determine the cause of an abnormality in gas-insulated switchgear based on the correspondence of values.

FIG. 4 shows the cause of abnormality occurrence and the pattern of partial discharge at that time. For example, it is known that discharge pulses are observed during the period of void discharge field. For this reason, the third
In step S4 of the figure.

When the count value of V raster 14 is 1 or 5 (or 1
. Display and output. When the cause of the abnormality is a sharp edge in 8Fs, a needle-shaped metal piece, or a poor contact between metal parts, a discharge pulse will be observed at the voltage phase shown in Figure 4. Therefore, in step S4 of FIG. 3, the discharge pattern is discriminated by successive comparison of the V raster 14 and the count value of the register 13, and the respective display and output are performed in steps 86, 87, 88, as in the case of void discharge. I'll do it at When a discharge pattern other than the above is observed, the cause is unknown, and this fact is displayed and output in step S9.

The above is an explanation of the four discharge patterns that are currently known, but if the cause of the abnormality due to the A4 discharge pattern is found in the future, it can be dealt with by increasing the address of register 14 to make the discharge pattern visible. It is. In this way, it is possible to automatically detect the secondary voltage of the voltage transformer and the secondary current of the current transformer connected to the ground wire, as well as the occurrence of an abnormality and the cause of the abnormality in the gas-insulated switchgear.

〔Effect of the invention〕

According to the present invention, it is possible to automatically detect both the abnormality and the cause of the abnormality in the gas insulated switchgear and perform preventive diagnosis without providing an additional mechanism inside the gas insulated switchgear.

[Brief explanation of drawings]

FIG. 1 is a route diagram showing the principle of the present invention, FIG. 2 is a drawing showing circuit waveforms, FIG. 3 is a flowchart, and FIG. 4 is a drawing showing causes of abnormality and patterns of partial discharge occurrence. 1... Main circuit conductor, 2... Breaker, 3... Voltage transformer. 4...Pacase, 5...Grounding wire, 6...Current transformer, 7...Width shaping device, 8...And gate, 9...
- Square wave converter, 10...clock, 11...counter, 12...counter. 13...Register, 14...Register 1st item 2nd item 20-, Mi side plate 1

Claims (1)

[Claims] 1. A voltage input circuit that inputs the secondary output of the voltage transformer connected to the grid, and a current input that inputs the secondary output of the current transformer for detecting discharge current connected to the grounding wire of the case of the gas-insulated switchgear. A gas insulation circuit is equipped with a circuit, and when one cycle of AC voltage is divided into appropriate time periods, discharge current is observed in each time period over one cycle of AC voltage, and based on the pattern of presence or absence of discharge current, gas insulation A preventive diagnostic method for gas-insulated switchgear, characterized by detecting abnormalities in the switchgear and their causes.