JP2013076589A - Insulation diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the detection sensitivity of partial discharge of ns order which occurs in a solid insulation device.SOLUTION: An insulation diagnostic device includes: a first detection electrode 4 directly provided on the surface of an isolation layer 2 structuring a solid insulation device; a second detection electrode 5 provided on the surface of the isolation layer 2 via a high frequency component delay member 6; a differential circuit 7 connected to the first detection electrode 4 and the second detection electrode 5; an integration circuit 9 connected to the differential circuit 7; a transmission cable like a coaxial cable 10 connected to the integration circuit 9 for transmitting a signal; and a processing circuit 11 connected to the transmission cable for processing a signal of partial discharge. The high frequency component delay member 6 attenuates and delays a signal whose frequency is ns order.

Description

  Embodiments described herein relate generally to an insulation diagnosis apparatus that diagnoses an insulation state of a solid insulation device such as a solid insulation switchgear molded with an insulation material.

  Conventionally, in a solid insulation switchgear in which a vacuum valve, a main circuit conductor and the like are molded with an epoxy resin, a detection electrode is provided on the surface of an insulation layer to detect a partial discharge generated due to insulation deterioration. (For example, refer to Patent Document 1). However, noise from the main circuit and grounding is superimposed on the detection electrode, which limits the detection sensitivity.

  On the other hand, it is known that two sets of detection electrodes are prepared and connected to a differential circuit to remove noise and improve the detection sensitivity of partial discharge. This is because the mounting location is different between one detection electrode and the other detection electrode, and the same superimposed noise is to be removed (see, for example, Patent Document 2). However, the same noise is not necessarily superimposed on both, and it is difficult to distinguish between the two if a partial discharge occurs on both.

JP 2009-168489 A JP 2000-55974 A

  The problem to be solved by the present invention is that two sets of detection electrodes for detecting a partial discharge are provided adjacent to a solid-insulated device of the object to be measured and processed by a differential circuit, so that the frequency to be superimposed is similarly μs. An object of the present invention is to provide an insulation diagnostic apparatus that can remove noise of the order and improve the detection sensitivity of the ns order signal generated by the partial discharge.

  In order to solve the above problems, an insulation diagnostic apparatus according to an embodiment is provided with a first detection electrode provided directly on the surface of an insulating layer constituting a solid-insulated device, and a high-frequency component delay member provided on the surface of the insulating layer. A second detection electrode, a differential circuit connected to the first detection electrode and the second detection electrode, an integration circuit connected to the differential circuit, and an integration circuit connected to the integration circuit A transmission cable for transmitting a signal, and a processing circuit for processing a partial discharge signal connected to the transmission cable, wherein the high frequency component delay member attenuates and delays a signal having a frequency of the order of ns. Features.

1 is a circuit diagram showing a configuration of an insulation diagnostic apparatus according to Embodiment 1 of the present invention. The figure explaining the measurement signal in the insulation diagnostic apparatus which concerns on Example 1 of this invention. The circuit diagram which shows the structure of the insulation diagnostic apparatus which concerns on Example 2 of this invention. The circuit diagram which shows the structure of the insulation diagnostic apparatus which concerns on Example 3 of this invention.

  The embodiment of the present invention detects a partial discharge signal propagating in an insulating layer with high sensitivity. Embodiments of the present invention will be described below with reference to the drawings.

  First, an insulation diagnostic apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a circuit diagram showing a configuration of an insulation diagnostic apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a diagram for explaining a measurement signal in the insulation diagnosis apparatus according to Embodiment 1 of the present invention. In addition, a solid insulation apparatus is demonstrated using an insulated bus.

  As shown in FIG. 1, the insulated bus is provided by applying a conductive paint to the surface of the insulating layer 2 and the insulating layer 2 formed by molding an epoxy resin around the central conductor 1 of the main circuit. It is composed of a ground layer 3.

  A plate-like first detection electrode 4 is directly provided on the surface of the insulating layer 2. That is, it is provided by being bonded with the same material as the insulating layer 2 or embedded at the time of molding. A plate-like second detection electrode 5 is provided on the surface of the insulating layer 2 via the high-frequency component delay member 6 in proximity to the first detection electrode 4. The high frequency component delay member 6 is made of a material having a low density such as a gelled silicon material or a foamed insulating material, and has a predetermined insulating thickness.

  The first detection electrode 4 and the second detection electrode 5 are connected to a differential circuit 7 that calculates a difference between two signals, and are input to an integration circuit 9 via an amplifier circuit 8. The output of the integrating circuit 9 is input to the processing circuit 11 that processes the measurement signal via the coaxial cable 10 (transmission cable). In the processing circuit 11, the magnitude and frequency of partial discharge are calculated to diagnose insulation deterioration. It may be installed in the front door of the solid insulation device or in the electric room that controls it, and operates with a commercial frequency power supply.

  Next, a case where partial discharge occurs in the insulating layer 2 will be described with reference to FIG.

  As shown in the upper part of FIG. 2, the first detection electrode 4 detects a signal in which the first noise n1 is superimposed on the first pulse p1 due to partial discharge. On the other hand, in the second detection electrode 5, as shown in the lower stage, the first noise n1 and the wave are generated in the second pulse p2 by partial discharge whose crest value is smaller than that of the first pulse p1 and the time width is extended. A signal on which the second noise n2 having substantially the same high value and time width is superimposed is detected.

  This is because a partial discharge propagating through the insulating layer 2 is directly detected by the first detection electrode 4, so that it has a high-frequency component with a rise time of several ns to several hundred ns and is detected as the first pulse p 1. . Further, most noise components have a rise time of several μs or more, and are detected as the first noise n1. It should be noted that high-frequency noise in the order of ns propagated from the central conductor 1 and the ground layer 3 has a large attenuation and is difficult to detect.

  On the other hand, since the second detection electrode 5 detects the high-frequency component through the high-frequency component delay member 6, the high-frequency component in the ns order due to the partial discharge is greatly attenuated and delayed as shown by the second pulse p2. However, the second noise n2 having a frequency on the order of μs is less likely to attenuate than the ns order, and is almost the same as the first noise n1. The attenuation in the order of ns can be adjusted by the material and the distance (thickness) of the high-frequency component delay member 6. For example, by using silicon gel having a thickness of several millimeters, the rise time of several ns is delayed to several μs. Can be made.

  If these signals are processed by the differential circuit 7, noise having a frequency on the order of μs is removed, and the detection sensitivity of an ns order signal due to partial discharge can be improved. When the wiring from the first detection electrode 4 and the second detection electrode 5 to the integration circuit 9 is shortened, noise coupled to the detection system can be suppressed. Moreover, since the 1st detection electrode 4 and the 2nd detection electrode 5 are adjoining, the same noise is detected and the big noise removal effect can be acquired by making this differential. Furthermore, since the signal is transmitted through the integration circuit 9, noise resistance can be improved.

  According to the insulation diagnostic apparatus of the first embodiment, the first detection electrode 4 and the second detection electrode 5 via the high-frequency component delay member 6 are provided directly on the surface of the insulating layer 2, and these signals are received. By processing with the differential circuit 7, it is possible to detect with high sensitivity a signal of high frequency component of ns order generated by partial discharge. Note that a noise component on the order of μs is similarly detected by the first and second detection electrodes 4 and 5 and can be removed.

  Next, an insulation diagnostic apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a circuit diagram showing a configuration of an insulation diagnostic apparatus according to Embodiment 2 of the present invention. The difference between the second embodiment and the first embodiment is that noise resistance is improved. In FIG. 3, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, signal detection circuits from the first and second detection electrodes 4 and 5 to the differential circuit 7, the amplification circuit 8, and the integration circuit 9 are accommodated in a metal shield container 12. The shield container 12 is connected to the ground layer 3. Further, the operation of the processing circuit 11 is performed by the battery 13. The battery 13 may be provided in a signal detection circuit such as the amplifier circuit 8.

  According to the insulation diagnostic apparatus of the second embodiment, in addition to the effects of the first embodiment, noise that enters the signal detection circuit from the first and second detection electrodes 4 and 5 to the integration circuit 9 and the intrusion from the power source. Noise can be reduced.

  Next, an insulation diagnostic apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 4 is a circuit diagram showing a configuration of an insulation diagnostic apparatus according to Embodiment 3 of the present invention. The third embodiment is different from the second embodiment in that an optical fiber is used for transmission. In FIG. 4, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, an electrical / optical converter 14 is connected to the integrating circuit 9, and a signal is transmitted through an optical fiber 15 (transmission cable). An optical / electrical optical converter 16 is also connected to the processing circuit 11 side.

  According to the insulation diagnostic apparatus of the third embodiment, in addition to the effects of the second embodiment, noise that enters the transmission system can be reduced.

  According to the embodiment as described above, a signal having a frequency of the order of ns can be measured with high sensitivity, and the partial discharge detection sensitivity can be improved.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel 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 scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Center conductor 2 Insulation layer 3 Ground layer 4 1st detection electrode 5 2nd detection electrode 6 High frequency component delay member 7 Differential circuit 8 Amplification circuit 9 Integration circuit 10 Coaxial cable 11 Processing circuit 12 Shield container 13 Battery 14, 16 Optical converter 15 Optical fiber

Claims (5)

A first detection electrode provided directly on the surface of the insulating layer constituting the solid insulating device;
A second detection electrode provided on the surface of the insulating layer via a high-frequency component delay member;
A differential circuit connected to the first detection electrode and the second detection electrode;
An integrating circuit connected to the differential circuit;
A transmission cable for transmitting a signal connected to the integrating circuit;
A processing circuit for processing a partial discharge signal connected to the transmission cable;
The insulation diagnostic apparatus, wherein the high frequency component delay member attenuates and delays a signal having a frequency of ns order.   2. The insulation diagnostic apparatus according to claim 1, wherein the first detection electrode, the second detection electrode, the differential circuit, and the integration circuit are housed in a metal shield container.   The insulation diagnostic apparatus according to claim 1, wherein the processing circuit is operated by a battery.   The insulation diagnostic apparatus according to any one of claims 1 to 3, wherein the transmission cable is an optical fiber.   The insulation diagnosis apparatus according to claim 1, wherein the high-frequency component delay member is silicon gel.

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