JP2013113691A - Insulation diagnosis apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation diagnosis apparatus in which partial discharge occurring from a solid insulation device can be detected with high sensitivity.SOLUTION: In an insulation diagnosis apparatus, partial discharge of a solid insulation device provided with a ground layer in its outer periphery is detected. In the insulation diagnosis apparatus, a surface potential is detected by a plurality of detection electrodes in contact with a surface of the ground layer. A differential section is disposed in proximity with the detection electrodes and calculates a potential difference of the surface potentials detected from the detection electrodes. A transmission section transmits a signal outputted from the differential section, and a detection processing section detects partial discharge on the basis of the signal transmitted by the transmission section.

Description

Embodiments described herein relate generally to an insulation diagnostic apparatus.

  As a method for monitoring the insulation state of a solid insulation device, there is known a method of measuring a pulse current due to partial discharge by connecting a through-type current transformer to a ground bus. This is because a weak high-frequency pulse current flows to the ground bus when a circuit breaker or the like housed in a solid-insulated device is deteriorated in insulation, and this is detected.

  Moreover, in the solid insulation apparatus provided with the grounding layer on the surface, it is known that partial discharge is detected by arranging a detection electrode on the surface.

  However, in the case of measuring by connecting a through-type current transformer to the ground bus, the pulse current due to the partial discharge is very weak, so that it is easily buried in noise superimposed from the external environment and difficult to detect. Specifically, noise such as electromagnetic waves from other electric devices is superimposed on a main circuit section such as a circuit breaker, and this also flows to the ground bus, making it difficult to detect partial discharge. For this reason, measures are taken to improve the detection sensitivity by providing a noise removal circuit or the like, but the partial discharge detection circuit becomes complicated.

  In addition, the measurement with the detection electrode arranged on the surface of the ground layer enables detection with higher sensitivity than the measurement using the above-described through-type current transformer, but the signal line from the detection electrode to the detector is used. It may be affected by external electromagnetic waves or may be affected by noise superimposed on the ground layer on the surface of the insulator.

JP 2009-168489 A

  The problem to be solved by the present invention is to provide an insulation diagnostic apparatus that can detect a partial discharge generated from a solid insulation device with high sensitivity.

  In the insulation diagnostic apparatus according to the embodiment, in the insulation diagnosis apparatus that detects partial discharge of a solid insulation device having a ground layer on the outer periphery, a plurality of detection electrodes brought into contact with the surface of the ground layer detect a surface potential. The differential unit is arranged so as to be close to the detection electrode, and calculates a potential difference between the surface potentials detected from the detection electrode. The transmission unit transmits a signal output from the differential unit, and the detection processing unit detects partial discharge based on the signal transmitted by the transmission unit.

The block diagram of the insulation diagnostic apparatus of 1st Embodiment, and the schematic diagram of the solid insulation apparatus to which this is applied. The (a) side view and (b) top view which show an example of arrangement | positioning of two detection electrodes and a differential part. The block diagram of the insulation diagnostic apparatus of 2nd Embodiment, and the schematic diagram of the solid insulation apparatus to which this is applied. The block diagram of the insulation diagnostic apparatus of 3rd Embodiment, and the schematic diagram of the solid insulation apparatus to which this is applied. The block diagram of the insulation diagnostic apparatus of 4th Embodiment, and the schematic diagram of the solid insulation apparatus to which this is applied. The block diagram of the insulation diagnostic apparatus of 5th Embodiment, and the schematic diagram of the solid insulation apparatus to which this is applied. (A) Side view and (b) Top view showing an example of the arrangement of three detection electrodes and a differential part arranged in a straight line. The (a) side view and (b) top view which show an example of arrangement | positioning of the three detection electrodes and the differential part which were arranged in a triangle shape. The block diagram of the insulation diagnostic apparatus of 6th Embodiment, and the schematic diagram of the solid insulation apparatus to which this is applied.

  Hereinafter, embodiments will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram of an insulation diagnostic apparatus according to the first embodiment and a schematic diagram of a solid insulation apparatus to which the insulation diagnosis apparatus is applied.

  The solid insulating device 1 includes a high voltage conductor 2, an insulating layer 3, and a ground layer 4.

In the solid insulating device 1, a high-voltage conductor 2 that is a main circuit member is molded with an insulating layer 3, and a ground layer 4 is provided on the outer peripheral surface of the insulating layer 3. The high voltage conductor 2 is made of a metal member such as copper or aluminum. The insulating layer 3 is formed of epoxy resin, polyethylene resin, silicon rubber, or the like, and the ground layer 4 is formed by applying a conductive paint such as carbon paint or silver paint.

  On the other hand, the insulation diagnostic device 5 includes a first detection electrode 6, a second detection electrode 7, a differential unit 8, an amplification unit 9, a transmission unit 10, and a detection processing unit 11. The transmission unit 10 includes an insulation pipe. 12. A coaxial cable 13 is provided.

The first detection electrode 6 and the second detection electrode 7 are brought into contact with the surface of the ground layer 4 to detect a potential, and the differential unit 8 calculates a potential difference between the detected surface potentials. The amplification unit 9 amplifies the signal from the differential unit 8, and the transmission unit 10 transmits the amplified signal. And the detection processing unit 11
Detects the presence or absence of partial discharge. In the insulation diagnostic apparatus of the first embodiment, a coaxial cable 13 housed in an insulation pipe 12 is used as the transmission unit 10.

  Here, when a partial discharge occurs in the insulating layer 3 of the solid insulating device 1, a current due to this partial discharge flows to the ground layer 4. This current causes a slight potential increase at a high frequency in the ground layer 4 due to the impedance of the ground layer 4. By detecting this potential increase, partial discharge can be detected.

Specifically, the first detection electrode 6 and the second detection electrode 7 are brought into contact with the surface of the ground layer 4, and the surface potential at each position is detected. The potentials detected by the first detection electrode 6 and the second detection electrode 7 are respectively input to the differential unit 8, and the potential difference between them is calculated. Since it is estimated that the noise included in the signal output from the first detection electrode 6 and the noise included in the signal output from the second detection electrode 7 are substantially equal, the differential unit 8 uses the mutual signal. By taking the difference, noise is canceled out, and a signal due to partial discharge can be detected with high sensitivity.

The signal output from the differential unit 8 is amplified by the amplification unit 9 and then transmitted to the detection processing unit 11 through the coaxial cable 13 accommodated in the insulating pipe 12. Based on the transmitted signal, the detection processor 11 detects the presence or absence of partial discharge.

By the way, the detection electrodes 6 and 7 are connected to the differential unit 8, and the differential unit 8 and the amplification unit 9 are connected to each other by wiring. The wiring path between the detection electrode 6 and the differential unit 8, the detection electrode 7 and the differential unit A so-called loop circuit is formed by three wiring lines connecting the detection electrode 6 and the detection electrode 7 via the ground layer 4.

  In order to prevent noise due to electromagnetic waves from the outside from entering, it is effective to reduce the area of the loop circuit, that is, to shorten the three lines.

  However, since a predetermined distance is required between the detection electrodes 6 and 7 in terms of detection accuracy, the length of the wiring connecting the first detection electrode 6 and the second detection electrode 7 to the differential unit 8 is set to be long. The degree of freedom of design is higher when it is changed. Therefore, the wirings connecting the detection electrodes 6 and 7 and the differential unit 8 are arranged so as to be the shortest (hereinafter, this is referred to as “disposing so as to be close”).

For example, as shown in FIGS. 2A and 2B, in the case where the detection electrodes 6 and 7 are arranged on the lower side of the substrate 14 and the differential portion 8 is arranged on the upper side, on the line connecting the detection electrodes 6 and 7. In addition, the differential portion 8 is arranged at a position where the distance from the first detection electrode 6 and the distance from the second detection electrode 7 are equal, and the wiring 15 is connected so as to penetrate through the substrate 14. Become. The arrangement shown in FIGS. 2A and 2B is an example for making the wiring 15 the shortest, and is not limited to this arrangement.

By arranging in this way, the area of the loop circuit formed by the ground layer 4, the detection electrodes 6, 7, the differential unit 8, and the wiring 15 is reduced, so that noise caused by electromagnetic waves entering the loop circuit is reduced. be able to.

Further, by shortening the wiring between the differential unit 8 and the amplification unit 9, noise due to electromagnetic waves can be reduced.

  Thus, by shortening the wiring between the detection electrodes 6 and 7 and the differential unit 8 and the wiring between the differential unit 8 and the amplification unit 9, the detection electrodes 6 and 7 to the amplification unit 9 are solid-insulated. Will be close to 1.

On the other hand, when diagnosing at a remote location, the distance between the amplifying unit 9 and the detection processing unit 11 becomes long. With a normal coated wire, the influence of electromagnetic waves between the amplifying unit 9 and the detection processing unit 11 is reduced. It becomes easy to receive.

Therefore, by connecting the amplifying unit 9 and the detection processing unit 11 with the coaxial cable 13 housed in the insulating pipe 12, the influence of electromagnetic waves can be greatly reduced, and it can be easily performed from a location away from the solid insulating device 1. In addition, partial discharge can be detected.

Moreover, the location where the partial discharge occurs can be specified by changing the location where the detection electrodes 6 and 7 are brought into contact with each other.

Specifically, it can be seen that when the potential difference between the detection electrodes 6 and 7 is large, the discharge location is close to the detection electrodes 6 and 7, and when the potential difference is small, the discharge location is far from the detection electrodes 6 and 7. Further, it can be seen from which detection electrode side the discharge portion is present, depending on the magnitude of the potential of the detection electrodes 6 and 7.

(Second Embodiment)
A second embodiment will be described with reference to FIG. In addition, the same part as each part of the insulation diagnostic apparatus of 1st Embodiment shown in FIG. 1 is shown with the same code | symbol. FIG. 3 is a configuration diagram of an insulation diagnostic apparatus according to the second embodiment and a schematic diagram of a solid insulation apparatus to which the insulation diagnosis apparatus is applied.

  The second embodiment differs from the first embodiment in that an optical fiber 17 and electro-optic converters 18 and 19 are used as the transmission unit 16 as shown in FIG.

Specifically, the signal output from the amplification unit 9 is converted into an optical signal by the first electro-optical conversion unit 18 and transmitted through the optical fiber 17. The partial discharge is detected by the detection processing unit 11 via the second electro-optical conversion unit 19.

The detection electrodes 6 and 7 and the differential unit 8, the differential unit 8 and the amplification unit 9, and the amplification unit 9 and the first electro-optical conversion unit 18 are connected by wiring, respectively, and the detection electrodes 6 and 7 and the differential unit 8 are connected. Are placed close to each other.

  In this way, by using the optical fiber 17 for transmission, the influence of electromagnetic waves can be further reduced than when the coaxial cable 13 is used, and highly sensitive partial discharge detection with excellent noise resistance is possible. Become.

(Third embodiment)
A third embodiment will be described with reference to FIG. In addition, the same part as each part of the insulation diagnostic apparatus in 1st Embodiment and 2nd Embodiment is shown with the same code | symbol. FIG. 4 is a configuration diagram of an insulation diagnostic apparatus according to the third embodiment and a schematic diagram of a solid insulation apparatus to which the insulation diagnosis apparatus is applied.

  The third embodiment differs from the first embodiment and the second embodiment in that a transmitter 21 and a receiver 22 are used as the transmission unit 20 as shown in FIG.

Specifically, the signal output from the amplifying unit 9 is wirelessly transmitted by the transmitter 21 and received by the receiver 22. Based on the signal from the receiver 22, the detection processing unit 11 detects partial discharge.

The detection electrodes 6, 7 and the differential unit 8, the differential unit 8 and the amplifying unit 9, the amplifying unit 9 and the transmitter 21 are connected by wiring, respectively, so that the detection electrodes 6, 7 and the differential unit 8 are close to each other. To place.

Since the frequency band of partial discharge is several hundred kHz to several hundred MHz, the influence of electromagnetic waves can be reduced by using radio waves in a frequency band that avoids this region. For example, a 2.4 GHz band that is a frequency band used in a wireless LAN or the like can be given.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIG. In addition, the same part as each part of the insulation diagnostic apparatus in 1st Embodiment thru | or 3rd Embodiment is shown with the same code | symbol. FIG. 5 is a configuration diagram of an insulation diagnostic apparatus according to the fourth embodiment and a schematic diagram of a solid insulation apparatus to which the insulation diagnosis apparatus is applied.

  As shown in FIG. 5, in the fourth embodiment, in the insulation diagnostic apparatus of the second embodiment, the differential unit 8, the amplification unit 9, and the first electro-optical conversion unit 18 are housed in a metal container 23. . With such a configuration, the influence of noise due to electromagnetic waves can be reduced, and highly sensitive partial discharge detection can be performed.

  FIG. 5 shows a case where the present invention is applied to the insulation diagnostic apparatus of the second embodiment, but it can also be applied to the insulation diagnosis apparatuses of the first embodiment and the third embodiment, and the same effect is obtained. be able to. Specifically, when applied to the insulation diagnostic apparatus of the first embodiment or the third embodiment, the differential unit 8 and the amplification unit 9 are housed in the metal container 23.

(Fifth embodiment)
A fifth embodiment will be described with reference to FIG. In addition, the same part as each part of the insulation diagnostic apparatus in 1st Embodiment thru | or 4th Embodiment is shown with the same code | symbol. FIG. 6 is a configuration diagram of an insulation diagnostic apparatus according to the fifth embodiment and a schematic diagram of a solid insulation apparatus to which the insulation diagnosis apparatus is applied.

  In the first to fourth embodiments, the two detection electrodes 6 and 7 are provided, but in the fifth embodiment, three or more detection electrodes are provided. FIG. 6 shows an example in which the third detection electrode 24 is provided in addition to the first detection electrode 6 and the second detection electrode 7 and the number of detection electrodes is three.

  The first detection electrode 6, the second detection electrode 7, and the third detection electrode 24 are brought into contact with the surface of the ground layer 4 to detect the surface potential. The potentials detected by the detection electrodes 6, 7, 24 are input to the differential unit 8, respectively. In the differential unit 8, the potential difference between the first detection electrode 6 and the second detection electrode 7, the potential difference between the first detection electrode 6 and the third detection electrode 24, and the potential difference between the second detection electrode 7 and the third detection electrode 24. Is calculated. The output signal is amplified by the amplifying unit 9 and then transmitted through the coaxial cable 13 accommodated in the insulating pipe 12. Then, the partial discharge is detected by the detection processing unit 11 based on the transmitted signal. Thus, when three or more detection electrodes are provided, the potential difference is calculated by the combination of the two selected detection electrodes.

The detection electrodes 6, 7, and 24 are connected to the differential unit 8, the differential unit 8 and the amplification unit 9 are connected by wiring, and the detection electrodes 6, 7, and 24 and the differential unit 8 are arranged close to each other.

For example, as shown in FIGS. 7A and 7B, when the detection electrodes 6, 7, and 24 are arranged on the straight line at equal intervals on the lower side of the substrate 14 and the differential unit 8 is arranged on the upper side, By arranging the differential portion 8 directly above the third detection electrode 24 and connecting the wiring 15 so as to penetrate the substrate 14, the wiring 15 becomes the shortest.

  Further, when a plurality of detection electrodes are arranged, the detection electrodes are not limited to a straight line, and can be arranged so as to form a polygon. As shown in FIGS. 8 (a) and 8 (b), when the detection electrodes 6, 7, and 24 are arranged so as to form a triangle, the differential portion 8 is arranged immediately above the center of gravity of the triangle, and the substrate 14 is mounted. By connecting the wiring 15 so as to penetrate, the wiring 15 becomes the shortest.

The arrangement shown in FIGS. 7 and 8 is an example for shortening the wiring 15 and is not limited to these arrangements.

Since the potential difference between the detection electrodes close to the partial discharge location becomes larger, the value becomes larger, so it is easier to identify the partial discharge location than when two detection electrodes are used, and multiple partial discharges occur simultaneously. This makes it easier to identify the position.

  For example, in the arrangement shown in FIG. 6, when the potential of the first detection electrode 6> the potential of the third detection electrode 24> the potential of the second detection electrode 7, the partial discharge location is on the first detection electrode 6 side. It can be estimated that there is. When the potential of the first detection electrode 6 = the potential of the third detection electrode 24> the potential of the second detection electrode 7, the partial discharge location is in the vicinity of the first detection electrode 6 and the third detection electrode 24. Can be estimated. Regarding these estimations, it is desirable to obtain data in advance through experiments or the like and store the data in the detection processing unit 11 as a database.

FIG. 6 shows a case where the present invention is applied to the insulation diagnostic apparatus of the first embodiment, but it can also be applied to the second to fourth embodiments, and the same effect can be obtained.

(Sixth embodiment)
A sixth embodiment will be described with reference to FIG. In addition, the same part as each part of the insulation diagnostic apparatus in 1st Embodiment thru | or 5th Embodiment is shown with the same code | symbol. FIG. 9 is a configuration diagram of an insulation diagnosis apparatus according to the sixth embodiment and a schematic diagram of a solid insulation apparatus to which the insulation diagnosis apparatus is applied.

  In the sixth embodiment, a portion (hereinafter referred to as a detection circuit) constituted by the first detection electrode 6, the second detection electrode 7, the differential unit 8, the amplification unit 9, and the transmission units 10, 16, and 20 is used. A plurality of components are provided, and one detection processing unit 11 detects partial discharge.

  By adopting such a configuration, it is easier to specify the partial discharge location than in the case of one detection circuit, and the position can be specified even when a plurality of partial discharges are generated at the same time as in the fifth embodiment. It becomes easy to do.

  Although FIG. 9 shows a case where the present invention is applied to the insulation diagnostic apparatus of the first embodiment, the present invention can also be applied to the second to fourth embodiments, and similar effects can be obtained.

  In addition, when applying to the insulation diagnostic apparatus of 4th Embodiment, in addition to what was mentioned above, the metal container 23 is also contained in a detection circuit.

  In addition, the insulation diagnosis device of the fifth embodiment and the insulation diagnosis device of the sixth embodiment can be combined, and in the insulation diagnosis device of the sixth embodiment, three or more in one detection circuit A detection electrode may be provided.

According to at least one embodiment described above, it is possible to provide an insulation diagnosis apparatus that can reduce the influence of noise due to electromagnetic waves and can detect a partial discharge generated from a solid insulation device with high sensitivity.

  In the above embodiment, the differential unit 8, the amplification unit 9, and the first electro-optic conversion unit 18 are configured by separate circuits and connected to each other. However, each of the above units is configured as one circuit (module). It may be configured.

Although several embodiments of the present invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof in the same manner as included in the scope and gist of the invention.

DESCRIPTION OF SYMBOLS 1 ... Solid insulation apparatus 2 ... High voltage conductor 3 ... Insulating layer 4 ... Grounding layer 5 ... Insulation diagnostic device 6 ... 1st detection electrode 7 ... 2nd detection electrode 8 ... Differential part 9 ... Amplifying part 10,16,20 ... Transmission Section 11 ... Detection processing section 12 ... Insulating pipe 13 ... Coaxial cable 14 ... Substrate 15 ... Wiring 17 ... Optical fiber 18 ... First electric light conversion section 19 ... Second electric light conversion section 21 ... Transmitter 22 ... Receiver 23 ... Metal container 24 ... third detection electrode

Claims (6)

In an insulation diagnostic device that detects partial discharge of a solid insulation device provided with a ground layer on the outer periphery,
A plurality of detection electrodes that contact the surface of the ground layer and detect a surface potential;
A differential unit arranged so as to be close to the detection electrode and calculating a potential difference of the surface potential detected from the detection electrode;
A transmission unit for transmitting a signal output from the differential unit;
An insulation diagnostic apparatus comprising: a detection processing unit that detects partial discharge based on a signal transmitted by the transmission unit.   The insulation diagnostic apparatus according to claim 1, wherein the transmission unit is a coaxial cable housed in an insulation pipe. The transmission unit is
A first electro-optical conversion unit that converts a signal output from the differential unit into an optical signal;
An optical fiber having one end connected to the first electro-optic converter and transmitting a signal from the first electro-optic converter;
The insulation diagnostic apparatus according to claim 1, further comprising a second electro-optical conversion unit connected to the other end of the optical fiber. The transmission unit is
A transmitter for wirelessly transmitting a signal output from the differential unit;
A receiver for receiving a signal from the transmitter;
The insulation diagnostic apparatus according to claim 1, comprising: The insulation diagnostic apparatus according to claim 1, further comprising a plurality of detection circuits including the detection electrode, the differential unit, and the transmission unit.   The insulation diagnostic apparatus according to claim 1, wherein at least the differential unit is housed in a metal container.

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