JP3086720B2 - Partial discharge detection system for gas insulated switchgear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detection system applied to a gas insulated switchgear in which power equipment is compactly housed in a grounded metal container.

[0002]

2. Description of the Related Art In recent years, gas insulated switchgear has become widespread and in operation due to the necessity of strengthening substation facilities in association with soaring land prices and increasing power supply in urban areas. As is well known, this gas insulated switchgear is configured by connecting a line including a switchgear such as a disconnector or a circuit breaker to a main bus and a line-side gas insulated bus. Various devices constituting such a gas insulated switchgear include a high-voltage charging unit housed in a grounded metal container together with an insulating gas such as SF6 gas, and an insulating spacer is arranged between adjacent grounded metal containers. It is configured.

Such a gas insulated switchgear has various advantages such as downsizing and reduction of the number of exposed charged parts, but has difficulty in maintenance diagnosis due to high performance and downsizing, and maintenance and repair work time. Disadvantages such as an increase in Therefore, in the gas insulated switchgear, in addition to the substation equipment control system that issues switching and tripping commands to the conventionally used circuit breakers, disconnectors, and grounding switches, the operating state of the substation equipment is normal. There is an increasing need for a preventive maintenance system capable of confirming the reliability of such a situation and enabling early detection and monitoring when an abnormality occurs.

The monitoring items of the above-mentioned preventive maintenance system include corona amount, gas moisture amount, gas component, gas pressure, gas temperature, gas density, and the like, whose measured values themselves do not change rapidly.
There are items that are quasi-stationary, such as oil level, oil pressure, oil temperature, and amount of cracked gas, and items that require processing within a short period of time, such as operating time of circuit breakers and disconnectors. for that reason,
As a normal monitoring method, the latter item is measured at the time of device operation, data is processed and calculated, the result is output and displayed, and the former quasi-stationary item is measured for a certain period of time. , Measurement and processing of data, and the result is output and displayed and stored.

[0005]

By the way, from the viewpoint of predicting a device abnormality in the monitoring items as described above,
One of the most important items is partial discharge detection (corona detection). For this partial discharge detection, many detection methods have been proposed. For example, JP-A-55-863
As disclosed in Japanese Patent Application Laid-Open No. 16-55260 and Japanese Patent Application Laid-Open No. 55-85260, a method of detecting partial discharge by a current transformer attached to a ground wire of a metal container,
As described in JP-A-7572, there is a method of locating the partial discharge generation region by the vibration acceleration of the surface of the metal container. However, these detection methods are:
Neither of these methods directly detect partial discharges generated inside the metal container, so to improve detection accuracy,
A large number of detectors had to be installed, which was inefficient. Also, it has been difficult to accurately determine the region where the partial discharge occurs.

The present invention has been proposed to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a high-density detector capable of efficiently locating a partial discharge generation area with a small number of detectors. An object of the present invention is to provide an accurate partial discharge detection system for a gas insulated switchgear.

[0007]

In a partial discharge detection system for a gas insulated switchgear according to the present invention, a line is drawn out from a main bus using a three-phase collective gas insulated bus on the line side, and the main bus and the line are connected. A single-phase gas-insulated switchgear for three phases, each having a switch, is disposed between the line-side three-phase gas-insulated bus and a line in the single-phase gas-insulated switchgear. A first partial discharge detector is installed in the vicinity of the connection with the three-phase gas-insulated bus on the side, and a second portion is disposed on the main bus side of the switch in each single-phase gas-insulated switchgear. A discharge detector is installed,
By comparing the output values of the first and second partial discharge detectors, the local discharge occurrence region is located.

[0008]

According to the partial discharge detection system of the present invention, each single-phase type gas-insulated switchgear in the line is connected to the vicinity of the connection with the three-phase collective gas-insulated bus on the line side and to each single-phase type gas-insulated bus in the line. Since the first and second partial discharge detectors are respectively installed on the main bus side of the switch in the gas insulated switchgear, the detection signal values of the first and second partial discharge detectors are compared. Accordingly, it is possible to determine whether or not a partial discharge has occurred in the three-phase collective gas-insulated bus on the line side and the region where the partial discharge has occurred. That is, when a partial discharge occurs in the three-phase gas-insulated bus on the line side, this partial discharge pulse is propagated to each single-phase gas-insulated switchgear, and the switching in each single-phase gas-insulated switchgear is performed. Attenuated by a container, a large number of insulating spacers, and contact portions. Therefore, the output level of the first partial discharge detector provided at the connection with the three-phase collective gas insulated bus on the line side is equal to the output level of the second partial discharge detector provided on the main bus side of the line.
Is higher than the output level of the partial discharge detector.

Therefore, by comparing the detection signal values of the first and second partial discharge detectors, it is possible to determine the presence / absence of partial discharge in the three-phase collective gas-insulated bus on the line side and the region where the partial discharge occurs. Can be. In particular, since the decay rate of the partial discharge pulse in the switch is high, the output level difference between the first and second partial discharge detectors is further increased, and the line-side 3
It becomes easier to determine whether or not a partial discharge has occurred in the phase-integrated gas-insulated bus and the region in which the partial discharge has occurred. In addition, the first,
Since the second partial discharge detector is installed in the single-phase gas insulated switchgear, higher detection sensitivity can be obtained, and partial discharge can be detected efficiently.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a partial discharge detection system for a gas insulated switchgear according to the present invention will be specifically described below with reference to FIGS.

First, FIG. 1 is a schematic plan view showing a part of a gas insulated switchgear to which a partial discharge detector system according to the present invention is applied, and FIG. 2 is an enlarged view of FIG. is there. In FIGS. 1 and 2, a partial discharge detector is provided on a line I connecting a main bus and a line-side three-phase collective gas-insulated bus. In this case, a partial discharge detector is actually installed not only in the line I but also in other lines, but since the configuration and the operation and effect are the same as those of the line I, Only the line I will be described.

As shown in FIGS. 1 and 2, in a circuit I, a bus disconnector (DS) 2 for each of three phases is connected to main buses 1A and 1B arranged in parallel. Is connected to a line-side three-phase collective gas-insulated bus (GIB) 4 via a circuit breaker (GCB) 3. As shown in FIG. 1, partial discharge detectors (first partial discharge detectors) 13A to 13C are provided at a single-phase branch portion between the line-side three-phase collective gas-insulated busbar 4 and the circuit breaker 3. The partial discharge detectors (second partial discharge detectors) 13D to 13F are provided between the circuit breaker 3 and the bus-side disconnector 2 of each phase.

FIG. 3 is a circuit diagram showing a circuit configuration of the partial discharge detector 13A. As shown in FIG. 3, the partial discharge detector 13A is connected to the insulating spacer 12 of the corresponding phase.
Of the buried electrode 14. In the figure, 8 is a ground metal container, and 15 is a high voltage conductor. Although not shown, the other partial discharge detectors 13B to 13F are also connected to the buried electrodes 14 of the corresponding insulating spacers 12 of the respective phases, similarly to the partial discharge detector 13A. It has exactly the same circuit configuration as the device 13A. Therefore, only the partial discharge detector 13A will be described below.

That is, as shown in FIG. 3, the partial discharge detector 13 connected to the buried electrode 14 of the insulating spacer 12
A denotes a filter 16 connected between the buried electrode 14 and the ground potential of the ground metal container 8, a detection amplification circuit 17, a peak detector / integration circuit 18, an A / D converter 19, an E / O
It comprises a converter 20, a battery 21, and a timer 22. Then, the filter 16 and the detection amplification circuit 1
7. The partial discharge detection signal detected by the peak detector / integration circuit 18 is digitized by the A / D converter 19, converted into an optical signal by the E / O converter 20, and then transmitted to the receiving side by the optical cable 23. It is to be transmitted.

The partial discharge detector configured as described above determines the presence or absence of a partial discharge by detecting an electromagnetic wave accompanying the partial discharge generated inside the gas-insulated equipment. Therefore, in the partial discharge detection system of this embodiment having such a partial discharge detector, it is possible to detect the partial discharge generated inside the metal container of the gas insulated switchgear as described below.

First, since the internal partial discharge of the gas-insulated equipment is related to the discharge phenomenon of SF6 gas whose rise is several ns, the signal generated by the partial discharge is also several hundred MHz.
It becomes an extremely high frequency electromagnetic wave up to z. In this case, the charging part of the gas-insulated equipment is housed in the grounded metal container 8, so that the electromagnetic wave of a frequency of several MHz or more due to the internal partial discharge generated in the grounded metal container 8 is not grounded metal. The container 8 will act as a waveguide. Therefore, a signal generated by the partial discharge propagates in the grounded metal container 8.

Then, as shown in FIG.
When a partial discharge pulse is generated between the buried electrode 14 and the ground metal container 8, the partial discharge pulse is generated by the capacitive load C 1 between the high-voltage conductor 15 and the buried electrode 14 of the insulating spacer 12. The voltage is divided by the capacitive load C2 between the container 8 and appears as a signal at the buried electrode 14 in the insulating spacer 12. In general, C2 is on the order of several hundreds of pc, and the larger C1 is, the higher the sensitivity to the partial discharge pulse is. On the other hand, when the value of C1 between the high-voltage conductor 15 and the buried electrode 14 is compared between the single-phase insulating spacer and the three-phase insulating spacer, the value of the single-phase insulating spacer disposed at the coaxial position is reduced. Is several tens of times larger than the value of the three-phase insulating spacer. Therefore, in this embodiment in which the partial discharge detector 13 is grounded to the buried electrode 14 of the single-phase insulating spacer, it is much higher than the case where the partial discharge detector is provided to the buried electrode of the three-phase insulating spacer. Detection sensitivity can be obtained, and partial discharge can be detected efficiently.

FIG. 4 is an output characteristic diagram showing an example of a detection signal when a partial discharge generated inside the gas insulated switchgear is detected using the partial discharge detection system of the present invention.
That is, in the line I shown in FIG. 2, when a partial discharge occurs in the line-side three-phase collective gas-insulated bus 4, this partial discharge pulse propagates in the line-side three-phase collective gas-insulated bus 4, The signal propagates to the line I through the single-phase branch.

In the line I, there are several switches such as the circuit breaker 3 and there are many insulating spacers and contact parts, so that the partial discharge pulse is attenuated. In particular, in the circuit breaker 3, the partial discharge pulse is greatly attenuated due to a difference in surge impedance, a capacitor, and the like. According to an example of the actual measurement data, the attenuation of the partial discharge pulse in the circuit breaker 3 is about 30 to 35%.
For this reason, the output level of the detector 13A installed in the single-phase branch portion near the line-side three-phase collective gas-insulated bus 4 is higher than the detector 13D installed on the main bus side via the circuit breaker 3. Become. Therefore, the two partial discharge detectors 13A, 1
By comparing the 3D detection signal values, it is possible to determine whether partial discharge has occurred in the line-side three-phase collective gas-insulated bus 4 and the region where the partial discharge has occurred.

As described above, according to the present embodiment, a small number of partial discharge detectors are connected to the single-phase branch portion on the line side of the line and the buried electrode of the single-phase insulating spacer inside the line. The detector can efficiently locate the partial discharge generation region of the line-side three-phase collective gas-insulated bus.

The present invention is not limited to the above-described embodiment. A floating electrode is provided in a grounded metal container of a gas insulated switchgear while being insulated from the grounded metal container. May be connected to a partial discharge detector.
In this case, the same effect as in the above embodiment can be obtained. In addition, the installation location of the partial discharge detector inside the line can be appropriately selected. Further, the present invention is not limited to a gas-insulated switchgear using a three-phase collective line-side gas-insulated bus, but is similarly applicable to a gas-insulated switchgear using a single-phase line-side gas-insulated bus. .

[0022]

As described above, according to the present invention, the first partial discharge detector is installed in the vicinity of the connection with the three-phase collective gas-insulated bus on the line side in each single-phase gas-insulated switchgear. A second partial discharge detector is installed on the main bus side of the switch in each single-phase gas insulated switchgear, and a partial discharge is generated by comparing the output values of the first and second partial discharge detectors. Since the area is located, it is possible to efficiently and accurately locate the area where the partial discharge occurs with a small number of detectors.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an embodiment of a partial discharge detection system for a gas insulated switchgear according to the present invention.

FIG. 2 is an enlarged view of FIG.

FIG. 3 is a circuit diagram showing a circuit configuration of a partial discharge detector in the embodiment of FIG.

FIG. 4 is an output characteristic diagram showing an example of a detection signal of a partial discharge detector when a partial discharge occurs in a line-side three-phase collective gas-insulated bus in the embodiment of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1A, 1B ... Main bus 2 ... Bus side disconnector 3 ... Circuit breaker 4 ... Line-side three-phase collective gas-insulated bus (line-side GIB) 8 ... Grounding metal container 12 ... Insulating spacer 13A-13F ... Partial discharge detector 14 ... Embedded electrode 15 ... High voltage conductor 16 ... Filter 17 ... Detection amplification circuit 18 ... Peak detector / integration circuit 19 ... A / D converter 20 ... E / O converter 21 ... Battery 22 ... Timer 23 ... Optical cable

Claims (1)

(57) [Claims] 1. A circuit is drawn out from a main bus using a line-side three-phase collective gas-insulated bus, and between the main bus and the line-side three-phase collective gas-insulated bus within the circuit. A single-phase gas-insulated switchgear for three phases, each having a switch, is arranged, and the line-side 3 in each of the single-phase gas-insulated switchgears is arranged.
A first partial discharge detector is provided in the vicinity of a connection portion with the batch-type gas insulated bus, and a second partial discharge detector is provided closer to the main bus than the switch in each of the single-phase gas insulated switchgears. A partial discharge detection system for a gas insulated switchgear, wherein a partial discharge occurrence area is located by comparing output values of the first and second partial discharge detectors.