JP4512042B2 - Partial discharge detector in switchboard - Google Patents

Description

  The present invention relates to a partial discharge detection device for detecting an electrical signal of partial discharge caused by an insulation abnormality in a switchboard, and more particularly, a voltage class 6.6 KV to 70 KV class cubicle filled with an insulating gas. This relates to a type switchboard.

  As an example of a conventional partial discharge detection device, a method of detecting a partial discharge signal using a metal electrode embedded in a spacer supporting a conductor as an antenna in a gas insulated switch of voltage class 70 KV to 500 KV is shown. (For example, Patent Document 1).

Japanese Patent Laid-Open No. 04-210709 (FIG. 2)

  However, the partial discharge detection apparatus using the antenna as disclosed in Patent Document 1 has the following problems. Since the spacer diameter depends on the tank diameter, the dimensions of the antenna are determined by the tank diameter and the insulation design, the range of the resonance frequency due to partial discharge is limited, and a wide range of resonance frequencies can be detected based on complex partial discharge phenomena. Absent. In addition, when a malfunction occurs in the spacer of the GIS in operation or when a malfunction occurs in the embedded antenna, it is necessary to replace the spacer, but the spacer is configured to connect two sections as a gas section. At the time of replacement work, it is necessary to release the gas in the two compartment tanks, which makes the work complicated. In addition, when an antenna is installed in the tank, it is necessary to install a part to store the sensor in the tank or install a part through which the detection signal wiring is passed, and new parts other than the sensor and sensor are required. There is a problem that costs increase.

  The present invention has been made to solve the above-described problems, and enables the design of an antenna having a high degree of freedom capable of detecting a wide range of resonance frequencies, widening the selection range of antenna characteristics, and S / N. An object of the present invention is to provide a partial discharge detection device having a high ratio and a low cost.

The partial discharge detecting device in the switchboard according to the present invention has a bushing formed of an insulator installed across the inside and outside of the tank wall, and is insulated from the tank that is grounded around the central conductor passing through the bushing. A plurality of metal electrodes having different inner dimensions embedded therein, a discharge detection circuit connected to any one of the plurality of metal electrodes, and an arithmetic display circuit, and a partial discharge detected by the metal electrode The signal accompanying this is input to the discharge detection circuit, and the output signal of the discharge detection circuit is input to the arithmetic display circuit and displayed.

A partial discharge detecting device in a switchboard according to the present invention includes a bushing formed of an insulator installed across the inside and outside of a tank wall of the switchboard, and a tank that is grounded around a central conductor penetrating the bushing. A plurality of metal electrodes that are insulated from each other and have different inner dimensions are embedded, a discharge detection circuit connected to any one of the plurality of metal electrodes, and an arithmetic display circuit, and the metal electrodes detect A signal associated with the partial discharge is input to the discharge detection circuit, and the output signal of the discharge detection circuit is input to the arithmetic display circuit and displayed, so that a complex partial discharge phenomenon occurring in the switchboard can be detected. The degree of freedom in designing an antenna capable of detecting a wide range of resonance frequencies becomes possible. That is, the antenna dimensions can be freely selected without being governed by the insulation design as in the prior art. As a result, the antenna characteristics have a wide selection range, and an excellent effect is achieved such that the S / N ratio is high, the cost is low, and the maintainability is improved due to the installation outside the tank wall.

Embodiment 1 FIG.
Hereinafter, the first embodiment will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a cubicle type switchboard according to the first embodiment and a partial discharge detection device. The switchboard 100 is provided with a high-voltage conductor 3 for passing a current into a tank 1 that is at a ground potential, a circuit breaker 6 for interrupting the current, a vacuum valve 7 and an operating rod 8 as its components, and the tank 1 An insulating gas 2 is sealed inside. Further, a plurality of bushings 4 are installed across the tank wall 1a portion of the tank 1 so that half is inside and half is outside, that is, an atmospheric atmosphere. The bushing 4 is formed of a solid insulator 10 or the like as shown in the sectional plan view of FIG. 2, and is an antenna insulated from a tank that is grounded around a central conductor 5 penetrating the bushing 4, for example, in a ring shape. A metal electrode 9 is embedded. A signal line 11 is connected to the metal electrode 9 to input a signal to the discharge detection circuit 13. The output signal of the discharge detection circuit 13 is connected to the arithmetic display circuit 14 via the signal line 11. As described above, the bushing 4 is made of the solid insulator 10, and the central conductor 5 for energizing the coaxial center is embedded. The metal electrode 9 is embedded in a solid insulator 10, and the metal electrode 9 as an antenna detects an electromagnetic wave signal accompanying partial discharge and is in electrical contact with other parts such as the tank 1 by a lead wire 15. Instead, the signal is input to the discharge detection circuit 13 by the cable 11 outside the bushing 4.

  That is, when an insulation problem occurs in the switchboard 100, for example, when a metal foreign object adheres to a high electric field part, an interface insulation failure of a solid insulator, a vacuum degree deterioration in the vacuum valve 7 occurs, A partial discharge occurs at the site and radiates electromagnetic waves. Electromagnetic waves propagate through metals and insulators. Therefore, the electromagnetic wave propagates to the outside of the tank 1 through the insulator 10 of the bushing 4 up to the metal wall which is the tank wall 1 a inside the tank 1. The bushing 4 is attached to the tank wall 1a across the inside and outside of the tank 1 in order to connect the tank 1 and external power cables and overhead lines (not shown). In the first embodiment, the bushing 4 does not need to match the tank diameter, and the minimum size due to the insulation design of the bushing 4 and the maximum size due to the size of the tank 1 are limited. Can be selected freely. Accordingly, the size of the ring-shaped metal electrode 9 to be an antenna embedded in the antenna can be freely selected, and a design that brings the antenna characteristics close to the required specifications becomes possible.

When a partial discharge phenomenon occurs in the switchboard, the resonance frequency of the antenna that detects this discharge is expressed as f = v / L using the resonance frequency f, electromagnetic wave propagation velocity v, and antenna length L. For example, when the tank diameter of a certain voltage class GIS is about 250 mm, the size of the embedded antenna is approximately the same as the tank diameter in consideration of the insulation design. The antenna length L is 250 × π when considered as a circumference. When calculated by the above equation, the resonance frequency f is about 200 MHz.
Thus, in the conventional GIS, the antenna diameter is determined based on the insulation design. Therefore, the resonance frequency f is uniquely fixed at about 200 MHz, and recently the demand is increasing. It is difficult to realize a discharge detection circuit having a high S / N ratio.

  On the other hand, in the cubic switchboard 100 of the same class as in the first embodiment, the depth width of the tank 1 corresponding to the portion where the bushing 4 is disposed is about 2000 mm. Considering a model in which three phases are arranged in a double busbar structure, the maximum diameter of the bushing 4 is approximately 330 mm, and the minimum diameter of the bushing 4 as viewed from the insulating structure is approximately 150 mm. The resonance frequency in the case of configuring can be selected between approximately 150 MHz and 400 MHz. Since the frequency characteristics of the discharge signal and noise vary depending on the discharge source, equipment configuration, and installation location, the part with less noise and the part with strong discharge signal are not uniquely determined. Therefore, it is possible to configure a partial discharge detection device including a metal electrode 9 having a higher S / N, that is, an antenna, with a wider selection range of antenna characteristics.

FIG. 1 shows an example in which the embedded metal electrode 9 during bushing is provided outside the tank wall 1a. However, if the metal electrode 9 is disposed inside the tank wall 1a, electromagnetic wave noise is generated from outside the tank 1. This is advantageous in that the S / N ratio is high. By adopting such a configuration, a highly sensitive partial discharge detection device with a higher S / N ratio can be realized. In addition, although the case where the shape of the metal electrode 9 was ring shape was shown, not only this but elliptical shape, semicircle shape, rectangular shape, or linear shape may be sufficient.
As shown in FIG. 3, bushings 4 are provided on the upper and lower tank walls 1 a of the switchboard 100, and each discharge detection circuit is connected to each metal electrode 9 embedded in the bushing 4 via a signal line 11. 13 and 13a and outputting a signal to the discharge detection circuits 13 and 13a. When one arithmetic display circuit is provided on the circuit connecting the discharge detection circuits 13 and 13a, any one of the partial discharge signals generated in the panel, Alternatively, both metal electrodes can be detected, and a partial discharge detection device having a higher S / N ratio is obtained.

  Further, the switchboard 100 shown in FIG. 1 according to the first embodiment shows an example in which the bushings 4 are installed on the upper and lower parts of FIG. 1, that is, the bushings 4 are installed on different tank walls 1 a constituting the switchboard 100. However, the present invention is not necessarily limited thereto, and a plurality of bushings 4 may be installed on the same tank wall.

Embodiment 2. FIG.
Next, a second embodiment will be described.
In the bushing 4 of the first embodiment, an example in which one ring-shaped metal electrode 9 is provided around the penetrating central conductor 5 is shown. However, as shown in FIG. A bushing 4a provided with ring-shaped metal electrodes 9a, 9b, 9c may be used. When the bushing 4a having such a configuration is adopted, even if the partial discharge generation conditions vary depending on the arrangement conditions of the internal components of the switchboard 100, the local installation location conditions, and the like, a plurality of standardized bushing 4a antennas are used. An optimal one of the metal electrodes 9a to 9c can be selected to be connected to the discharge detection circuit 13, and partial discharge detection can be performed with a high S / N ratio.
The bushing 4a in which the plurality of metal electrodes 9a to 9c shown in FIG. 4 are embedded may be replaced with the bushing 4 shown in FIG. In this case, the discharge detection circuit 13 may be connected to any one of the metal electrodes 9a to 9c having the same diameter, or may be connected to metal electrodes 9a to 9c having different diameters. In addition, although the case where the metal electrode 9 has a ring shape with different diameters has been shown, in the case of an elliptical shape, a semicircular shape, a rectangular shape, or the like, the inner dimensions may be different.
By increasing the degree of freedom in selecting the antenna diameter, there is an effect that partial discharge detection with an improved S / N ratio can be performed.

Embodiment 3 FIG.
In FIG. 1 shown in the first embodiment, the discharge detection circuit 13 is displayed as a single unit. However, by increasing the number of sensors, a highly accurate insulation diagnosis can be performed. There is almost no bushing attached to the switchboard, and there are almost a few bushings per phase. Therefore, when the signal line 11a is connected to the metal electrode 9 which is an antenna as shown in FIG. 5 and two signals are input to the oscilloscope 22, the time difference between the signals captured by the respective antennas 9 can be acquired. Electromagnetic waves propagate in the gas at the same speed as the speed of light. Therefore, if the time difference between the signals is known, the relative distance from each discharge source to the antenna 9 can be calculated from the transmission speed of the electromagnetic wave, and the position of the partial discharge source can be determined. Further, as a system, the device after the cable is not a device to which only the oscilloscope can be applied, and the discharge detection circuit 13 shown in the first embodiment may be provided with a function of measuring the time difference with an electronic circuit. As described above, it is possible to obtain a partial discharge detection device that can determine a discharge position with an existing component without using a new antenna.

Embodiment 4 FIG.
In the fourth embodiment, the metal electrode 9 embedded in the bushing 4 is also used as a sensor for detecting a voltage during operation of the switchboard 100. That is, as shown in FIG. 6, the voltage detector 16 is connected by branching from the circuit connecting the discharge detection circuit 13 and the metal electrode 9. By adopting such a configuration, it is possible to detect the operating voltage, and there is an effect that information for maintenance is abundant.

  Embodiments 1 to 4 of the present invention can be used for a partial discharge detection device for a switchboard.

It is a figure which shows the partial discharge detection apparatus by Embodiment 1 of this invention. It is a cross-sectional projection view which shows the bushing by Embodiment 1 of this invention. It is a figure which shows the partial discharge detection apparatus by Embodiment 1 of this invention. It is a sketch which shows the bushing by Embodiment 2 of this invention. It is a figure which shows the partial discharge detection apparatus by Embodiment 3 of this invention. It is a figure which shows the partial discharge detection apparatus by Embodiment 4 of this invention.

Explanation of symbols

1 tank, 1a tank wall, 4, 4a bushing, 5 center conductor,
9, 9a, 9b, 9c metal electrode, 13 discharge detection circuit, 14 arithmetic display circuit,
16 Voltage detector, 100 switchboard.

Claims (5)

A partial discharge detection device in a switchboard in which an insulating gas is sealed,
A bushing formed of an insulator that is installed across the inside and outside of the tank wall of the switchboard, and a plurality of metal electrodes that are insulated from the tank that is grounded and have different inner dimensions around the central conductor that passes through the bushing Is embedded, and includes a discharge detection circuit connected to any one of the plurality of metal electrodes and an arithmetic display circuit, and a signal associated with a partial discharge detected by the metal electrode is detected by the discharge detection. A partial discharge detection device in a distribution board, wherein the partial discharge detection device is input to a circuit, and an output signal of the discharge detection circuit is input to and displayed on the arithmetic display circuit. A partial discharge detection device in a switchboard in which an insulating gas is sealed,
A plurality of bushings formed of insulators installed on different tank walls separated from each other across the inside and outside of the tank wall of the switchboard, and a tank that is grounded around a central conductor that penetrates the bushings A plurality of metal electrodes having different inner dimensions are embedded, and a discharge detection circuit connected to each of the metal electrodes having the same inner dimension of any one of the plurality of metal electrodes for each of the plurality of bushings; An arithmetic display circuit provided on a circuit connecting the discharge detection circuits to each other, and a signal associated with the partial discharge detected by the metal electrode is input to the discharge detection circuit, and the output of the discharge detection circuit A partial discharge detection device in a switchboard, wherein a signal is input to the arithmetic display circuit and displayed. A partial discharge detection device in a switchboard in which an insulating gas is sealed,
A plurality of bushings formed of an insulator installed across the inside and outside of the tank wall of the switchboard, and a plurality of bushings that are insulated from the tank that is grounded and have different inner dimensions around the central conductor that penetrates the bushings And a discharge detection circuit connected to the metal electrode having the same inner dimension of any one of the plurality of metal electrodes for each of the plurality of bushings, and the discharge detection circuit connected to each other And an arithmetic display circuit on the circuit to be operated, a signal accompanying partial discharge detected by the metal electrode is input to the discharge detection circuit, and an output signal of the discharge detection circuit is input to the arithmetic display circuit. A partial discharge detection device in a switchboard, characterized by being displayed. A partial discharge detection device in a switchboard in which an insulating gas is sealed,
A plurality of bushings formed of insulators installed on different tank walls separated from each other across the inside and outside of the tank wall of the switchboard, and a tank that is grounded around a central conductor that penetrates the bushings A plurality of metal electrodes that are insulated and have different inner dimensions are embedded, and a discharge detection circuit that is connected to each of the metal electrodes having different inner dimensions of each of the plurality of metal electrodes for each of the plurality of bushings; A circuit for connecting the discharge detection circuits to each other, and an arithmetic display circuit; a signal associated with the partial discharge detected by the metal electrode is input to the discharge detection circuit; and an output signal of the discharge detection circuit is A partial discharge detection device in a switchboard, wherein the partial discharge detection device is inputted to an arithmetic display circuit and displayed. 5. The function according to claim 2, wherein the discharge detection circuit is provided with a function of measuring a time difference caused by a signal captured by a metal electrode provided in the plurality of bushings. The partial discharge detection apparatus in the switchboard as described in a term .

Images