JPH02271264A - Partial discharge detector - Google Patents

Abstract

PURPOSE:To enhance detection sensitivity and reliability by preventing the effect due to noise by providing a detection electrode in power machinery in an insulated state and measuring the potential of said electrode. CONSTITUTION:When partial discharge is generated in power machinery, a partial discharge current flows to a metal container 2. A part of the partial discharge current flows to the earth though an earth wire 13 but, since the frequency of the partial discharge current is high and an earth circuit containing the earth wire 13 has impedance, a part of the partial discharge current flows to a detection electrode 5, 5' through stray capacity. Therefore, the electrodes 5, 5 are charged and the potentials of the electrodes 5, 5 rise. The potential rises of the electrodes 5, 5' is measured using voltmeters 8, 8' for example, vibration capacity type potentiometers through voltage detectors 7, 7' to detect the partial discharge generated in the power machinery.

Description

Detailed Description of the Invention [Industrial Application Field] The first invention and the second invention provide a partial discharge detection device for detecting partial discharge generated inside power equipment to which a high voltage is applied. It is related to.

[Junior Blind Jutsu]

A conventional partial discharge detection device will be explained based on the drawings. Fourth
The figure is a cross-sectional view of a power device equipped with a conventional partial discharge detection device disclosed in, for example, Japanese Utility Model Publication No. 58-855. In the figure, a metal container 2 is grounded via a ground @ 13, and a high potential conductor 1 is housed therein, insulated and fixed by an insulating spacer 3. Further, an insulating medium 4, for example an insulating gas 4, is sealed inside the metal container 2. On the other hand, a part of the outer surface of the metal container 2 has a dielectric material 11
is coated with a conductive substance detection electrode 1 on top of the coating.
0 is deposited. Detection electric piix.

is used as a detection end of a partial discharge detector and is connected to, for example, a current pulse measuring device 12 to the partial discharge detector.

When a partial discharge occurs in a portion of the high potential conductor 1 inside a power device equipped with the conventional partial discharge detection device as described above, a partial discharge current flows into the metal container 2. A part of this current flows to the ground through the grounding wire 13, but since the partial discharge current has a high frequency, most of it flows to the MIE body 11 having a lower impedance. Therefore, the detection electrode 1
By measuring the current value of 0 using the current pulse measuring device 12, the occurrence of partial discharge is detected.

[Problem to be solved by the invention]

As mentioned above, the conventional partial discharge detection device has a detection electrode IO provided on the outside of the metal container 2, and is easily affected by noise due to electromagnetic waves generated in the space outside the metal container 2 due to discharge, etc. However, due to such noise, it was not possible to detect small partial discharges that occurred in the detected area. For this reason, in the conventional partial discharge detection device, the lower limit of the detection range must be set to a certain degree, which causes a problem that the detection sensitivity is narrow.

The present invention has been made to solve the above problems, and aims to prevent the influence of noise on a partial discharge detection device, increase detection sensitivity, and obtain a partial discharge detection device with high detection sensitivity and reliability. This is the purpose.

[Failure to solve the problem]

A partial discharge detection device according to a first aspect of the present invention includes a metal container sealed with an insulating medium and grounded, a high potential conductor insulated and housed in the metal container, and arranged at least in a portion near the inner surface of the metal container. , a detection electrode insulated from a metal container, and a voltage detection means for measuring the potential of the detection electrode.

A partial discharge detection device according to a second aspect of the invention includes a metal container sealed with an insulating medium and grounded, a high potential conductor insulated and housed in the metal container, and arranged near the inner surface of the metal container,
a plurality of detection electrodes insulated from the metal container; a plurality of voltage detection means for measuring the potential of each of the detection electrodes;
The apparatus further includes a voltage comparison calculation circuit that compares the outputs of the respective voltage detection means.

[Effect]

In the power equipment equipped with the partial discharge detection device of the first invention, when a local partial discharge occurs in a high potential conductor in a metal container filled with an insulating medium, such as an insulating gas, this partial discharge occurs. A detection electrode disposed near the portion is charged with an electric charge through the stray capacitance of the insulating gas. Since the potential of the detection electrode is always measured by the voltage detection means, the voltage detection means detects an increase in the potential of the detection electrode due to the occurrence of partial discharge, thereby detecting the occurrence of partial discharge.

In power equipment equipped with the partial discharge detection device of the second invention, when a local partial discharge occurs in a high potential conductor in a metal container filled with an insulating medium, for example an insulating gas, the Measured by established means,
The output signal of this voltage detection means is input to the voltage comparison calculation circuit. Furthermore, outputs from other detection electrodes disposed at other locations within the metal container are input to the voltage comparison calculation circuit via other voltage detection means. This voltage comparison calculation circuit compares each output from the detection electrode, and when a local partial discharge occurs, detects the difference and generates an output.

〔Example〕

First Embodiment The partial discharge detection device of the first invention will be described below with reference to FIGS. 1 and 2 showing the first embodiment. FIG. 1 is a side sectional view of a power equipment equipped with a partial discharge detection device according to @1 embodiment of the first invention, and FIG. 2 is a direction in which a high potential conductor of the power equipment shown in FIG. I: A front sectional view taken along an intersecting plane. In the figure, a metal container 2 is grounded via a grounding wire 13, and a high potential conductor 1 is housed therein, insulated and fixed by an insulating spacer 3. Also, inside the metal container 2 is an insulating medium 4, for example an insulating gas 4.
is included. Along the inner surface of the metal container 2, at least one detection wl pole 5.5' is arranged at a desired position with a predetermined gap from the inner surface, and a detection ttL pole 5.5' is formed of a conductor and the insulating support 6
．． They are insulated and fixed to the vicinity of the inner surface of the metal container 2 via 6'. The voltage detection means for measuring the potential of the detection electrodes 5, 5' includes, for example, a voltage detector 7.7' and a voltmeter 8.8'. The voltage detectors 7.7' penetrate the wall of the metal container 2 and are disposed near the respective detection electrodes 5.5'. It is fixed through an insulator. The detection ends of the voltage detectors 7, 7' are formed of a disc-shaped conductor with a diameter of about 10 fl, and their end faces face the outer surface of the detection mold faj5.5'.

The outputs of the voltage detectors 7.7' are respectively input to voltmeters 8.8', and the potentials of the detection electrodes 5, 5' are constantly measured.

Next, the operation of the partial discharge detection device of the first embodiment will be explained. When a partial discharge occurs inside the power equipment described above, a partial discharge current flows into the metal container 2 . A part of the partial discharge current flows to the ground through the ground wire 13, but the partial discharge current has a high frequency (because the ground circuit including the ground wire 13 has impedance, part of the partial discharge current flows out to the ground through the ground wire 13). The detection electrode 5.5 passes through the stray capacitance of the insulating gas 4.
Flows to '. Therefore, the detection electrode 5.5' is charged with electric charge, and the potential of the detection W1 pole 5.5' increases. This increase in the potential of the detection electrodes 5, 5' is detected by the IIE pressure detector 7.
．． By measuring with a voltmeter 8.8', for example, an oscillating capacitance type electrometer, via a voltmeter 7', the partial discharge detection device of the first embodiment detects partial discharge occurring inside the power equipment. .

゛Second Embodiment The partial discharge detection device of the second invention will be explained below with reference to FIG. 3 showing the second embodiment. FIG. 3 is a side sectional view of a power device equipped with a partial discharge detection device according to a second embodiment of the second invention.

In this second embodiment, similar to the first embodiment described above, the power equipment includes a grounded metal container 2 and a high potential conductor 1 fixed inside the metal container 2 with an insulating spacer 3. An insulating medium 4, for example an insulating gas 4, is placed inside the metal container 2.
is included. Further, inside the metal container 2, a plurality of detection wL poles 5,5' having the same shape are arranged along the inner surface of the metal container 2, with a predetermined gap from the inner surface. The voltage detection means includes non-contact voltage detectors 7, 7' and voltmeters 8, 8' as in the first embodiment.
The detection electrodes 5 and 5' are provided in numbers corresponding to the plurality of detection electrodes 5 and 5'.

The outputs of the voltage detectors 7.7' are respectively input to voltmeters 8.8', and the potential of the detection electrodes 5.5' is constantly measured. The output signals from each voltmeter 8.8' are input to a voltage comparison calculation circuit 9, respectively.

Next, the operation of the partial discharge detection device of the second embodiment will be explained. As in the first embodiment described above, when a partial discharge occurs inside the power equipment, the detection electrodes 5.5' are charged and the potential of the 11 detection poles 5.5' increases. Generally, weak partial discharges occur uniformly on the surface of the high potential conductor 1 inside the power equipment, and each detection electrode 5.
The potential at 5' rises in the same way. However, since the potential value of each detection electrode 5.5' is input to the voltage comparison calculation circuit 9 via each voltmeter 8.8', each potential value is compared within the voltage comparison calculation circuit 9. If they are the same value, the output of the voltage comparison calculation circuit 9 is zero. If a local partial discharge that causes insulation degradation inside the power equipment occurs, only the detection electrode 5 provided near the source will have a higher potential than the other detection electrodes 5', and each detection type 1is
, s', the voltage comparison calculation circuit 9 generates an output.

In the first and second embodiments described above, the voltage detection means is a non-contact type voltage detector 7.7' and the detection electrode 5.7' is used as the voltage detection means.
Although the potential of the capacitor 5' is detected, the voltage detecting means may be used to detect the voltage across the capacitor by directly connecting the detection electrode 5.5' to one of the capacitors provided inside the power equipment.

Furthermore, by forming the detection electrode 5.5' in a cylindrical shape smaller than the inner diameter of the metal container 2 and providing it near the entire circumference of the inner surface of the metal container 2, it is possible to further increase the detection sensitivity of partial discharge. Become.

As described above, according to the first invention, the detection electrode is insulated and provided inside the power equipment, and the potential of the detection electrode is measured. The present invention is not easily affected by external electromagnetic waves, and can detect even small partial discharges, which has the effect of providing a highly reliable partial discharge detection device.

According to the second invention, by inputting the output of each voltage detection means to the voltage comparison calculation circuit, a weak partial discharge that uniformly occurs in a high potential conductor does not generate an output, and the internal power equipment This is a partial discharge detection device that generates an output when a local partial discharge that causes insulation degradation occurs. Therefore, there is an effect of obtaining a highly reliable partial discharge detection device.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a power device equipped with a partial discharge detection device according to an embodiment of the first invention, FIG. 2 is a front sectional view of the power device shown in FIG. 1, and FIG. 1 is a side sectional view of a nine force device equipped with a part number w/l detection device according to an embodiment of the invention;
FIG. 4 is a side sectional view of a power device equipped with a conventional partial discharge detection device. In the figure, l is a high potential conductor, 2 is a metal container, 4 is an insulating medium, 5.5' is a detection electrode, 7 and 7' are voltage detectors,
8.8' is a voltmeter, and 9 is a voltage comparison calculation circuit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A metal container filled with an insulating medium and grounded, a high potential conductor insulated and housed in the metal container, and a detection electrode arranged near at least a portion of the inner surface of the metal container and insulated from the metal container. A partial discharge detection device, comprising: voltage detection means for measuring the potential of the detection electrode. (2) A metal container filled with an insulating medium and grounded, a high potential conductor insulated and housed in the metal container, and a plurality of detection electrodes arranged near the inner surface of the metal container and insulated from the metal container. A partial discharge detection device comprising: a plurality of voltage detection means for measuring the potential of each of the detection electrodes; and a voltage comparison calculation circuit for comparing outputs of the respective voltage detection means.