JPS62166713A - Apparatus and method of detecting partial discharge in gas insulated electric equipment - 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] [Industrial Application Field] The present invention relates to a partial discharge detector for gas-insulated electrical equipment, and particularly to an improvement of a partial discharge detector for detecting partial discharge in an insulating support member that supports a charging conductor. Regarding.

[Conventional technology]

Gas-insulated switchgear, gas-insulated busbars (or sealed busbars), and the like are known as gas-insulated electrical equipment. All of these devices house charging conductors in metal containers. The charging conductor is supported by an insulating support member such as an insulating spacer.

Because of this structure, partial discharge in the insulating support member must be accurately detected from the outside.

As the insulating support member, an insulating spacer that divides the inside of a metal container into several gases, a rod-shaped insulating member that simply supports a charging conductor, and the like are known.

Next, a sealed busbar will be explained as an example. The charging conductor of a sealed busbar, that is, the busbar conductor, is supported by an insulating spacer molded with epoxy resin or the like in a cylindrical metal container, and insulation between it and the busbar conductor is maintained by filling an insulating gas in the metal container. ing. On the surface of the insulating spacer configured in this way,
Partial discharge occurs due to the adhesion of dust and the like, and if the partial discharge continues for a long period of time while voltage is being applied, it will promote tree-shaped discharge erosion and its progression, causing a serious accident.

Detection of these partial discharges has been studied for some time, and for insulating spacers whose flange portions are made of insulating material, an auxiliary electrode is provided on the exposed outer circumferential surface of the insulating spacer to detect the capacitance partial voltage. A method for detecting discharge has been proposed.

FIGS. 5(a) and 5(b) show an example of the configuration of such a conventional partial discharge detection method, and use an insulating spacer as an insulating support member. The metal container 4 is provided with a flange 4a, and an insulating spacer 2 is sandwiched between the metal container 4 and the flange 4a of another metal container 4, and the three are connected by being tightened with bolts (not shown).

As the insulating spacer 2, a disc-shaped or cone-shaped one is used, and since it is molded from epoxy resin, it is a dielectric material. Therefore, by providing the first electrode 5 on the outer circumferential surface of the insulating spacer 2 exposed to the outside of the metal container 4 while being electrically insulated from others and in close contact with the charging conductor 1, a predetermined capacitance can be established between the first electrode 5 and the charging conductor 1. can get. As the first electrode 5, a conductive tape or a conductive paint is used.

The first electricity like this! l! 5 does not require a dedicated insulating spacer 2 because the potential can be easily taken out of the metal container 4 using a conventional insulating spacer 2.

This first electrode 5 has a lead wire 51 using a coaxial cable.
is connected to one end of a detector 8 having a differential amplifier, and the flange 4a is connected via a lead wire 61,
Serves as input for detection.

The electrical equivalent circuit in such a configuration is shown in Figure 5 (b).
). That is, the capacitive container C of the insulating spacer 2 between the first electrode 5 and the charging conductor 1, the flange 74a
and the capacitance C2 between the second electrode 5 are connected in series,
Both ends of the capacitance C2, that is, the first electrode 5 and the flange 4
A is connected to the detector by leads 51 and 61.

Note that the partial discharge pulse Pu flows through the capacitors C and C2 and is detected by a detector.

[Problem that the invention seeks to solve]

Such conventional detection methods have the following disadvantages. That is, in general, various miscellaneous continuous phase currents including pulsed currents such as switching surges flow through the metal container 4 which surrounds the high voltage charging part and has a grounded structure. On the other hand, since the first electrode 5 also plays the role of a kind of antenna for spatial radio waves such as broadcast waves, the noise level entering the detector 8 is high, so these external noises are not related to partial discharges. There are many cases where it is difficult to distinguish it from a signal.

FIG. 6 is an example of a method proposed to improve the above-mentioned disadvantages. (See Japanese Patent Publication No. 60-16163.) In FIG. 6, the second electrode 6 is attached to the flange 4a of the metal container 4 via an insulating member 7.

By adjusting the shape, area, etc. of each electrode so that the same external noise is induced in the first electrode 5 and the second electrode 6, and taking the differential of the signals induced in these electrodes, This is intended to improve the detection sensitivity of partial discharge signals. However, it is extremely difficult to adjust the shape and area of the electrodes in order to make the externally induced signals on the first and second electrodes 5 and 6 the same level, and the noise induced on each electrode is high frequency. Therefore, it is extremely rare for these noises to be completely in phase, so even if the signals induced at each F and pole are differentiated, external noise cannot be reduced much, which is a problem that needs to be solved. there were.

The present invention has been made in consideration of the above points, and by significantly reducing external noise, partial discharges occurring in insulating support members such as insulating spacers can be easily and highly sensitively detected from outside the metal container. An object of the present invention is to provide a partial discharge detector for gas-insulated electrical equipment and a method therefor.

[Means for solving problems]

In order to achieve the above object, according to the present invention, a charging conductor is supported by an insulating support member in a metal container filled with an insulating gas, and the outer periphery of the first electrode is attached to the outer periphery of the insulating support member. A second electrode insulated from the first electrode and electrically conductive to the metal container is provided, the first and second electrodes are input to the detector via a coaxial cable, and the coaxial cable is insulated and a conductive member is provided. The conductive member connects the second electrode to the metal case of the detector.

Further, a second electrode is provided insulated from the first electrode attached to the outer peripheral part of the insulating support member and the metal container, and further a second electrode is provided.
A third electrode is provided on the outer periphery of the electrode, which is insulated from the first and second electrodes and electrically connected to the metal container, and is connected to the detector by a coaxial cable with the first and second electrodes. Then, this coaxial cable is covered with an insulated conductive member, and the third electrode is connected to the metal case of the detector by this conductive member, so that C2 << C3. In both cases, the coaxial cable is insulated and covered with a conductive material, and the conductive material connects the electrode covering the first electrode, the metal container, and the metal case of the detector. Since it is completely shielded, various miscellaneous phase currents flowing in the metal container flow through the outer surfaces of the metal container, the electrode to which the conductive member is connected, the conductive member, and the metal case, so that they do not flow into the coaxial cable. There isn't. Therefore, external noise can be significantly reduced, and partial discharge generated in the insulating support member can be detected easily and with high sensitivity from outside the metal container.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In FIG. 1, a first electrode 5 facing the charging conductor 1 is provided on the outer periphery of the insulating spacer 2. As shown in FIG. Further, a second electrode 10 is provided so as to be electrically connected to the metal container 4 so as to electromagnetically shield the first electrode 5. These first and second
The voltage generated between the electrodes 5 and 10 is input to the detector 30. The RfU member 71 covering the coaxial cable 70 connects the second electrode 10 and the detector 30.
Connect with the metal case. Note that a shield ring 3 is embedded inside the insulating spacer 2.

FIG. 2 shows details of the main part of FIG. 1, that is, the signal extraction part. The first electrode 5 is attached to the outer periphery of the insulating spacer 2 to form an electrostatic capacitance IC shown by a dotted line mainly using the insulating spacer 2 as a dielectric. This first
A second electrode 10 is provided to electromagnetically shield the electrode 5 and to be electrically connected to the flange 4a, and between the first electrode 5 and the second electrode 10, for example, a Teflon (trade name) sheet is provided. An insulating member 11 like this is provided to form a capacitance C2 shown by a dotted line.

A detector 30 connected to the first electrode 5 and the second electrode 10 is housed in a metal case 30a along with an amplifier 31 and an E10 converter 32, and is connected to a monitoring station (not shown) via an optical cable 33. In addition, the coaxial cable 70 has a core wire 5.
1 and a sheath 61 that covers the main body.

The first electrode 5 and one terminal of the amplifier 31 of the detector 30 are connected by the core wire 51 of the coaxial cable 70, and one end of the sheath 61 of the coaxial cable 70 is connected to the other terminal of the amplifier 31. The other end of the sheath 61 of the coaxial cable 70 is connected to the inner surface of the second electrode 10, that is, to the insulating spacer 2 side. Furthermore, coaxial cable 70
One end of a cylindrical conductive member 71, such as a sheath, provided to shield the sheath 61 of the second electrode 1
The other end is connected to the outer surface of the metal case 30a of the detector 30.

With this configuration, various miscellaneous interphase currents flowing in the metal container 4 are transmitted to the metal container 4, the second electrode 10, the conductive member 71. Since it flows on each outer surface of the metal case 30a of the detector 30, it does not flow into the first electrode 5 and the sheath 61.

Furthermore, since the electronic circuits of the first and second electrodes 5, 10 and the detector 30 are completely electromagnetically shielded from the outside, the influence of spatial radio waves propagating through the air can be completely eliminated.

Furthermore, if the electric signal is converted into an optical signal by an E10 converter in the detector 30, and the signal is transmitted to the receiver side (not shown) of a monitoring station, for example, by an optical cable 33, it is possible to eliminate noise intrusion during signal transmission, and to insulate the signal. Partial discharge detection of insulating support members such as spacers becomes possible with extremely high sensitivity.

Next, another embodiment of the present invention will be described with reference to FIGS. 3 and 4. The same parts and parts having the same functions as those in FIGS. 1 and 2 are given the same cylinder numbers.

In FIG. 3, a first electrode 5 facing the charging conductor 1 via an insulating support member, such as an insulating spacer 2, is provided on the outer periphery of the insulating spacer 2 to be insulated from the metal container 4, and furthermore, this first electrode 5 and a second electrode 15 is provided insulated from the metal container 4, and these first and second electrodes 5
, 15 and these first and second electrodes 5
, 15 is electrically connected to the metal container 4 and provided with a third electrode 20. The detector 30 has first and second
The potential generated between the electrodes 5 and 15 is input via a coaxial cable 70. A cylindrical conductive member 71 covering the coaxial cable 70 connects the third electrode 20 and the detector 30.
Connect with the metal case. As shown in FIG. 4, which will be described later, the capacitance C2 shown by the dotted line between the first and second electrodes 5 and 15 is the capacitance C2 shown by the dotted line between the second electrode 15 and the third electrode 20. The gaps between these electrodes are appropriately selected based on the capacitance C1. An insulating member 11 such as an insulating paint is provided as a dielectric on the capacitor C1 side, and the capacitor C2
An insulating member 11 such as a Teflon (trade name) sheet is provided as a dielectric on the side, thereby forming C2<<C3. If such conditions are met, there is no problem with detection sensitivity and good detection sensitivity can be obtained.

When each electrode is arranged in this way, the first electrode 5 and the second electrode
Since the electrode 15 is electrically shielded by the third electrode 20, noise and the like will not enter the first and second electrodes 5 and 15 from the outside, improving partial discharge detection sensitivity.

FIG. 4 shows details of the main part of FIG. 3, that is, the signal extraction section. First electric tl! l! 5 is attached to the outer periphery of the insulating spacer 2, and a second electrode 15 is provided on the outer periphery insulated from the first electrode 5 and the metal container 4.

The third electrode 20 is provided on the outer periphery of the first and second electrodes 5 and 15 in order to electrically shield them, so as to be electrically insulated from these electrodes and conductive to the metal container 4. It is being

An insulating member 11 is inserted between the first, second and third electrodes 5.15.20. The first electrode 5 has a detector 30
A coaxial cable 70 connected to one terminal of the amplifier 31 of
One end of the sheath 61 of the coaxial cable 70 is connected to the other terminal of the amplifier 31, and the other end of the sheath 61 is connected to the insulating spacer 2 side of the second electrode 15. .

A cylindrical conductive member 71, such as a sheath, provided to further shield the sheath 61 of the coaxial cable 70
One end of the conductive member 71 is connected to the outside of the third electrode 20, and the other end of the conductive member 71 is connected to the outer surface of the metal case 30a of the detector 30.

According to such a configuration, various miscellaneous interphase currents flowing through the metal container 4 are transmitted through the metal container 4, the third electrode 20, and the sheath 7.
1 and metal case 30a, it does not flow into the first and second electrodes 5, 15 or the input section of the detection section 30.

Furthermore, since the electronic circuits of the first and second electrodes 5, 15 and the detector 30 are completely electromagnetically shielded from the outside,
The influence of spatial radio waves propagating through the air can also be completely eliminated.

Furthermore, by converting the electrical signal into an optical signal using an E10 converter in the detector 30 and transmitting the signal to the receiver side using an optical cable, it is possible to eliminate noise intrusion during signal transmission. Partial discharge in the support member can be detected.

〔Effect of the invention〕

As described above, according to the present invention, an insulating support member that supports a charging conductor housed in a metal container is formed so as to be sandwiched between the metal containers, and a first electrode is provided on the outer periphery of this insulating support member. Further, a second electrode is provided on the outer periphery, and the first and second electrodes and the detector are connected by a coaxial cable, and a conductive conductor covering the coaxial cable is connected to the metal container via the second electrode. and a metal case of the detector to shield the electrode, the coaxial cable, and the detector, and a second invention connects the first electrode and the second electrode to the detector via the coaxial cable, The third electrode and the metal case of the detector are connected by a conductive conductor that covers the coaxial cable, and is formed so that C 2 < C3, and further shields the first and second electrodes, the coaxial cable, and the detector. By doing so, both the first and second inventions significantly reduce external noise, and detect partial discharges in gas-insulated electrical equipment that can easily and sensitively detect partial discharges occurring in the insulating support member from outside the metal container. A device and a method thereof can be provided.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of one embodiment of the present invention. 3 and 4 are sectional views of other embodiments of the present invention, FIGS. 5(a) and 5(b) show conventional embodiments, FIG. 5(,) is a sectional view, and FIG. b) is its equivalent circuit diagram, and FIG. 6 is a sectional view of the conventional embodiment. ■...Charging conductor, 2...Insulating spacer,
4...Metal container, 4a...Flange 5...
・First electrode, 10.15... second electrode,
11... Insulating member, 20... Third electrode,
30... Detector, 30a... Metal case, 51... Core wire, 61... Sheath. 70... Coaxial cable, 71... Conductive member.

Claims (7)

[Claims] (1) A charging conductor is supported by an insulating support member in a metal container filled with an insulating gas, and the first electrode is electrically connected to the outer periphery of the first electrode attached to the outer periphery of the insulating support member. A second electrode is provided that is insulated from the metal container and electrically connected to the metal container, and the potentials generated at each of the first and second electrodes are input to the detector via a coaxial cable,
A partial discharge detector for gas-insulated electric equipment, characterized in that the coaxial cable is insulated and covered with a conductive member, and the second electrode and the metal case of the detector are connected by the conductive member. (2) The first electrode and one of the input terminals of the detector are connected by a core wire of a coaxial cable, and the second electrode and the other input terminal of the detector are connected by a sheath of the coaxial cable that shields the core wire. A portion of the gas-insulated electrical equipment according to claim 1, further comprising a conductive member that insulates and covers the coaxial cable and connects the second electrode and the metal case of the detector. Discharge detector. (3) Connect one end of the sheath of the coaxial cable to one of the input terminals of the detector, attach the other end of this sheath to the surface of the second electrode on the insulating support member side, and connect one end of the conductive member to the metal case. 3. The partial discharge detector according to claim 2, wherein the conductive member is connected to a surface of the second electrode opposite to the insulating support member. (4) A charging conductor is supported by an insulating support member in a metal container filled with an insulating gas, and the first electrode is electrically connected to the outer periphery of the first electrode attached to the outer periphery of the insulating support member. A second electrode is provided that is insulated from the metal container and electrically connected to the metal container, and the potentials generated at each of the first and second electrodes are input to the detector via a coaxial cable, and the coaxial cable is insulated from the second electrode. A method for detecting partial discharge in gas-insulated electrical equipment, comprising: covering the insulating support member with a conductive member, connecting the metal container and the metal case with the conductive member, and detecting partial discharge in the insulating support member. (5) A charging conductor is supported by an insulating support member in a metal container filled with an insulating gas, and the second electrode is insulated from the first electrode attached to the outer periphery of the insulating support member and the metal container. A third electrode is provided on the outer periphery of the second electrode and is insulated from the first and second electrodes and electrically connected to the metal container. The potential generated at each electrode is input to the detector via a coaxial cable, and this coaxial cable is covered with a conductive member insulated from the coaxial cable.
and the metal case of the detector, and the first electrode is connected to the metal case of the detector.
The capacitance between the electrode and the second electrode is C_2, the capacitance between the second electrode and the third electrode is C_3, and C_2<<C_3. A partial discharge detector for gas insulated electrical equipment, characterized in that: (6) The first electrode and one of the input terminals of the detector are connected by a core wire of a coaxial cable, and one end of the sheath of the coaxial cable that shields the core wire is connected to the insulating support member side of the second electrode. , the other end of the sheath is connected to the other input terminal of the detector, one of the conductive members is connected to the surface of the third electrode opposite to the insulating support member, and the conductive member 6. A partial discharge detector for gas-insulated electrical equipment according to claim 5, wherein the other end of the partial discharge detector is connected to a metal case of the detector. (7) A charging conductor is supported by an insulating member in a metal container filled with an insulating gas, and a second electrode is provided insulated from the first electrode attached to the outer periphery of the insulating support member and the metal container. Further, a third electrode is provided on the outer periphery of the second electrode, the third electrode is insulated from the first and second electrodes and is electrically connected to the metal container, and the first and second electrodes are electrically connected to each other. The potential generated in each of the above is input to the detector via a coaxial cable, the coaxial cable is covered with a conductive member insulated from the coaxial cable, and the third electrode and the metal case of the detector are connected by the conductive member, The capacitance between the first electrode and the second electrode is C_2, and the capacitance between the second electrode and the third electrode is C_3.
A method for detecting partial discharge in gas-insulated electrical equipment, characterized in that the insulating support member is formed such that C_2<<C_3, and partial discharge of the insulating support member is detected.