JPS5830555B2 - Koden Atsukikinobunhouden Kenshiyutsuhouhou Oyobi Sonosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for detecting partial discharge in high voltage equipment.

For example, during actual system operation of high-voltage power equipment such as transformers, the occurrence of partial discharge may cause an insulation breakdown accident.

Once such an accident occurs, it will have extremely serious consequences, such as disruption or stoppage of the power system.

For this reason, partial discharges are detected in high-voltage equipment during actual system operation to prevent equipment breakdown accidents.

There are two conventional techniques for measuring partial discharge in high-voltage equipment during actual operation: an electrical method and an acoustic method.

The former will be explained using the power transformer shown in FIG. 1 as an example.

Partial discharge pulses generated in the primary and secondary windings 2 and 3 wound around the iron core 1 are transferred to the PD taps 4 and 5 of the bushing.
Detection is performed by the detection impedance 6 connected to the
The electrical method is used for measurement via the amplifier 8 and display device 9 shown in the figure.

However, since this electrical method is connected to the transformer during actual operation (the overhead wire 6 of the power transmission line is connected to the overhead wire 6), the overhead wire 6 acts as an antenna and prevents inductive noise and electrical corona from the power transmission line from entering the partial discharge measurement circuit. However, sensitive measurements cannot be expected.

In addition, if this electrical method is adopted as an automatic monitoring device, the measurement system will generate sudden loud noises and is likely to cause malfunctions.

The other acoustic method is to attach an ultrasonic microphone to the outer wall of the equipment's tank and detect internal partial discharge sounds.

This method is less affected by induced noise from overhead wires and airborne corona, and is more suitable for on-site testing than electrical methods.

However, it has the disadvantage that it is sensitive to the sound of vibrating machinery inside the transformer, foreign objects hitting the tank wall, the sound of moving animals, etc., or the sound of rain, and the sensitivity is not good.

In order to eliminate the above-mentioned drawbacks, the present invention has been made to accurately detect the occurrence of partial discharge by detecting electromagnetic waves generated when partial discharge occurs in the equipment tank using the antenna probe G. The purpose of the present invention is to obtain a partial discharge detection device for high-voltage equipment that can be used in high-voltage equipment.

The present invention will be described below with reference to the drawings, taking a power transformer as an example.

In FIG. 3I, reference numeral 11 denotes a transformer tank, in which the transformer body 12 and insulating oil are stored.

Lead 13 derived from winding 12a of transformer body 12
is led out to the outside via a bushing 14 attached to the transformer tank 11, and connected to an overhead wire (not shown).

An antenna probe 15 is attached to a location inside the transformer tank 11 where a high electric field is not applied.

As shown in FIG. 4G, the antenna probe 15 is arranged so that it passes through the opening of the transformer tank 11 and its detection end is placed in the oil.

The antenna probe 15 is placed inside a cylindrical electromagnetic shielding case 16 that covers the opening of the transformer tank 11, and a partition wall 16 is formed on the inner surface of the central part of the electromagnetic shielding case 16.
It is oil-tightly supported by a.

The other end of the antenna probe 15 is an electromagnetic shielding case 16
Amplifier (with built-in battery) 17 stored in the other room of
and is connected to a display device (not shown) via a cable 18.

The other chamber of the electromagnetic shielding case 16 is covered by a rear lid 16b that houses an amplifier (with built-in battery) 17.

However, in the partial discharge detection device ζ configured as described above, when a partial discharge occurs in the transformer tank 11, 1
An electromagnetic wave having a frequency component of 0 to 100 MHz is generated, and this is transmitted to the transformer tank 111? It can be detected by the antenna probe 15 attached to C.

Such a partial discharge detection device has the following effects compared to conventional electrical methods and acoustic methods.

That is, (a) the antenna probe 15 that detects electromagnetic waves is not directly connected to the winding 12a, so it is less likely to pick up noise entering from the overhead wire.

(b) The antenna probe 15 does not detect abnormal sounds such as vibrations and noise from equipment and does not malfunction.

(/→ The antenna probe 15 is installed inside the transformer tank 11 and the electromagnetic shielding case 16 (because they are installed in these areas, they act as a shielding chamber)
There is no noise coming from the outside.

As described above, the partial discharge detection device for high voltage equipment according to the present invention is much more accurate than conventional electrical and acoustic methods, and also improves the directivity of the antenna probe.
By rubbing G so that the direction of the antenna probe can be changed from the outside, it is also possible to locate the partial discharge source.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams showing a conventional electrical partial discharge detection device, FIG. 3 is a sectional view schematically showing a partial discharge detection device according to the present invention, and FIG. 4 is a circuit diagram showing a partial discharge detection device according to the present invention. FIG. 2 is an enlarged cross-sectional view showing an enlarged main part. 11...Transformer tank, 12...High voltage equipment body, 15...Antenna probe, 16
・・・・・・Electromagnetic shield case.

Claims (1)

[Claims] 1. An antenna probe whose detection end is placed in oil is attached to an equipment tank containing internal insulating oil and a high-voltage equipment main body, and when a partial discharge occurs in the equipment tank (this occurs A method for detecting partial discharges in high voltage equipment by detecting electromagnetic waves (thereby detecting partial discharges). The opening is oil-tight (
This partial discharge detection device for high-voltage equipment consists of an antenna probe that is attached to the antenna probe and whose detection end is placed in oil, and an electromagnetic shielding case that covers the outer periphery of the antenna probe.