JPS6355474A - Detecting device for internal abnormality of electrical equipment - Google Patents

Abstract

PURPOSE:To improve detection accuracy of partial discharge by constituting the titled device so that a detector for detecting an electric signal generated in a conductive container, through a dielectric is provided, and sampling of a vibration waveform is started by a signal which has been detected by the detector. CONSTITUTION:In a conductive container 1, insulating gas G, and a conductor 2 in the axial length direction in the center of the container 1 are contained, and on the outside surface of the container 1, a vibrometer 4, and a detector 15 which has been connected to a connecting flange 1a through a connecting wire l are provided. A signal which has been detected by the vibrometer 4 is applied to a memory part 6b through an amplifier 5 and an A/D converter 6a. On the other hand, a signal which has been detected 15 is applied to a sampling command part 10 through a filter 20, and in case when an inputted signal is larger than a threshold value, a sampling command signal is generated. By this command signal, sampling data are stored 6b. In an arithmetic part 7, the data which has been stored already, and the data which has been inputted newly are added, and brought to a cumulative addition. Its accumulated value is given to a deciding part 8, and whether an internal abnormality of an electrical equipment exists or not is decided.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for detecting abnormalities such as partial discharges in electrical equipment, and more specifically, for detecting partial discharges occurring inside electrical equipment with high accuracy. This invention relates to an internal abnormality detection device.

[Prior art]

A bus bar in a gas insulated switchgear (GIS) has an insulating gas and a conductor arranged in a metal tube, and is generally constructed as shown in FIG. 4. Such an internal abnormality detection device for electrical equipment is disclosed in Japanese Patent Application No. 61-3777, for example.
It is shown in No. 4. In FIG. 4, a circle for supporting the conductor 2 disposed inside the metal tube 1.1 is shown between the connecting flanges 1a and 18 of the metal tubes 1, 1, which are filled with an insulating gas G. Both metal tubes 1.degree.l are connected to each other with a peripheral edge 3a of a plate-shaped support insulator 3 interposed therebetween. In order to detect the partial discharge generated in the conductor 2 inside the metal tube 1, a vibration meter 4 is attached to the outer surface of the metal tube 1, and the signal detected by the vibration meter 4 is transmitted to the A /D conversion section 6a and memory section 6b. The signal sampled by the sampling unit 6 is sent to the calculation unit 7
is given to the determination unit 8 via. Sampling command unit 1
0 creates a signal synchronized with the zero point of the AC voltage corresponding to the AC voltage applied to the conductor 2, and uses this signal to instruct the sampling unit 6 to start sampling.

The detection operation by this internal abnormality detection device is as follows. Now, when a partial discharge occurs in the conductor 2 as shown in Figure 5 (al), the metal tube 1 vibrates mechanically due to the partial discharge, and a vibration waveform as shown in Figure 5 is detected by the vibration meter. 4
Detected in The sampling command unit 10 gives a signal synchronized to the time point when the AC voltage is zero to the sampling unit 6, whereby the vibration meter 4 detects the signal and starts sampling the signal that is amplified by the amplifying unit 5. That is, each time a sampling command signal is input from the sampling command unit 10, sampling is started 0 times (for example, 1000 times) in an extremely short cycle (for example, 10 μs). The sampling state within nine frames in FIG. 5 (C1 is the top of FIG. 5) is shown in an enlarged manner.

Then, such sampling is repeated N times. The data obtained by one sampling is
The data are sequentially stored in the memory sections 6b. The calculation unit 7 also has n memories, and repeats the operation of reading n sampling values from the memory unit 6b, cumulatively adding their absolute values □ one after another, and storing them in the memory.

The cumulative value obtained by repeating data sampling and addition N times in this way is the same as the waveform detected by the vibration type 4 at the same period as the sampling command signal given in synchronization with the zero point of the AC voltage. The waveform will be emphasized as shown in FIG. 5 (dl), and the partial discharge generated within the electrical equipment can be clearly detected.

[Problem that the invention seeks to solve]

The above-described abnormality detection device for detecting partial discharge occurring in the bus bar can reliably detect partial discharge occurring in synchronization with the voltage cycle. However, since partial discharges do not always occur in synchronization with the voltage cycle, there is a problem that abnormalities due to partial discharges that occur asynchronously cannot be detected.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide an internal abnormality detection device that can detect with high precision even abnormalities caused by partial discharges that occur in electrical equipment without synchronization with the voltage cycle.

[Means for solving problems]

The internal writing device for an electrical device of the present invention includes a conductive container/detector that detects an electric signal generated in the container via a dielectric, and starts sampling a vibration waveform based on the signal detected by the detector. The structure is as follows.

[Effect]

Partial discharge occurs around a conductor in a conductive container to which a high voltage is applied due to insulation deterioration or the like. Mechanical and nuclear vibrations of the conductive container due to this partial discharge are detected by a vibration meter. On the other hand, an electric signal such as a high frequency voltage due to the generated partial discharge is generated between the connecting portions of the conductive containers that interconnect the conductive containers via the dielectric. This electrical signal is detected to start sampling the vibration waveform of the mechanical vibration of the conductive container, and a large number of samplings are performed. Repeated sampling is performed in the same manner, the sampling data is cumulatively added, and an internal abnormality is determined based on the cumulative value.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 1 is a block diagram of an internal abnormality detection device according to the present invention applied to a busbar.

In FIG. 1, a conductive container 1.1 houses an insulating gas G and a conductor 2 disposed at the center of the conductive container 1 along the axial direction. The conductor 2 is supported by airtightly penetrating the center of a dielectric supporting edge 3 having a tapered surface, with the center being slightly deviated from the periphery. The peripheral part of the support insulator 3 is interposed between the connecting flange 1a+la of the conductive container 1.1, and both conductive containers 1, 1 are connected to the support insulator 3, which is a dielectric.
It is connected across the . A vibration meter 4 for detecting mechanical vibrations is attached to the outer surface of the conductive container 1.1.

The signal detected by this vibration meter 4 is given to the amplification section 5, and the signal amplified by the amplification section 5 is sent to the A of the sampling section 6.
/D conversion section 6a to memory section 6b.

On the other hand, the conductive container 1 to which the vibration meter 4 is attached and the connection flange la of each of the conductive container 1 connected to the container
, la has a connection line l.

One end of l is connected, and the other end is connected to both connecting flanges la,
It is connected to a detector 15 consisting of a high frequency transformer that detects the high frequency voltage generated between la. The signal detected by the detector 15 is provided to the sampling command unit 10 via a filter 20 that passes high frequency components. The sampling command unit 10 compares the level of the signal input from the filter 20 with a threshold level determined as a level at which it can be determined that partial discharge has occurred, and determines that a signal with a level higher than the threshold level is input. If so, a sampling command signal is issued. That is, when a high-frequency voltage electric signal is generated between the connecting flanges la and la due to partial discharge occurring within the conductive container 1, a sampling command signal is given to the sampling section 6. Each time a sampling command signal is input, the sampling unit 6
A trigger signal is issued to perform a large number of samplings at the short predetermined period described above. Then, the sampled data is sequentially stored in n memory sections 6b of the sampling section 6. The calculation unit 8 adds the already stored data and the newly sampled data. The sampling unit 6 and the calculation unit 7 also repeat such data sampling and addition N times to cumulatively add the data. Then, the cumulative value is given to the determining section 8, and the determining section 8 determines whether or not there is an internal abnormality in the electrical equipment based on the result.

When an internal abnormality detection device configured as described above is installed, for example, on the busbar of a gas-insulated switchgear, if a partial discharge as shown in FIG. The partial discharge causes mechanical vibrations as shown in FIG. 2(b) in the conductive container 1, and the vibration meter 4 detects this vibration. A high frequency voltage as shown in FIG. 2(e) is generated between the connecting flanges la and la, and the detector 15 detects this. If it is higher than that, it is compared with a predetermined threshold value to determine that it is a partial discharge, and if it is exceeded, the sampling command unit 10 gives a signal to the sampling unit 6 to command the start of sampling. The mechanical vibration signal is sampled once at a very short period as shown in FIG. The sampling state within the light frame in FIG. 2 [d+ is the mountain in FIG. 2] is shown in an enlarged manner. While the same sampling is repeated N times, the arithmetic unit 7 cumulatively adds the absolute values of the data of the N times of repeated sampling.

When such an addition process is performed, the connection flange 1a+la
High-frequency signals detected in between and noise-like signals that have no specific time relationship are generated at random times even if they are added each time sampling, so the increase in numerical value with the number of additions is small. Connection flange Ia, l
The sampled value of the vibration waveform sampled in response to the high-frequency voltage generated between
) is obtained. Then, this detected waveform is given to the determining section 8, and an internal abnormality in the electrical equipment is detected by determining the magnitude of the signal level.

FIG. 3 is a block diagram showing another embodiment of the present invention,
In this embodiment, the sampling command section 10 includes a level change section 1.
0a to periodically change the threshold level described above.

In this way, there is a period ' between the connecting flanges la and la.
To prevent a sampling command signal from being generated due to noise when a threshold level is high even when a large noise is generated and the signal is input to a sampling command section 10. Can be done. Therefore, even if a noise signal is mixed into the high frequency voltage generated between the connecting flanges 1a+1a, it is possible to eliminate the influence thereof.

In this example, the internal abnormality detection device was applied to the busbar of the gas-insulated switchgear, but it can also be applied to busbars other than the gas-insulated switchgear, or to electrical appliances such as gas-insulated transformers that house electrical equipment together with insulating gas. Widely applied to equipment,
A similar effect can be obtained.

In addition, in this embodiment, the command signal for starting sampling was obtained from the voltage generated between the connecting flanges of the conductive container 1 that face each other with the support insulator 3 interposed therebetween; however, this is not limited to this. An electrode may be formed on the outer surface via a dielectric material, and the voltage may be obtained from the voltage generated between the electrode and the conductive container 1.

〔effect〕

As described in detail above, the present invention determines the point at which sampling of mechanical vibrations due to partial discharge is started based on the electrical signal generated in the conductive container due to the partial discharge generated inside the electrical equipment. Even partial discharges that occur out of synchronization with the applied alternating current voltage can be accurately detected, and the detection accuracy of partial discharges can be greatly improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an internal detection device according to the present invention applied to a bus bar, Fig. 2 is a waveform diagram for explaining the operation of the device of the present invention, and Part 3 is a block diagram showing another embodiment of the device of the present invention. 4 is a block diagram of a conventional internal abnormality detection device applied to a busbar, and FIG. 5 is a waveform diagram for explaining the operation of the conventional device. 1... Conductive container 1a... Connection flange 2...
・Conductor 4... Vibration meter 6... Sampling part 7.
...Arithmetic section 8...Determination section 10...Sampling command section 15...Detector (transformer) In the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A vibration meter attached to a conductive container that houses the main body of the electrical equipment, a sampling unit that repeatedly samples the signal obtained by the vibration meter, cumulatively adds the sampling values, and determines whether or not there is an internal abnormality in the equipment based on the results. an internal abnormality detection device for an electrical device, comprising: a detector for detecting an electrical signal generated in the conductive container via a dielectric; and a means for determining the electrical signal generated in the conductive container; 1. An internal abnormality detection device for an electrical device, comprising: a sampling command unit that instructs a sampling unit to start sampling.