JPH04123781A - Lightning arrester - Google Patents

Abstract

PURPOSE:To apply a test voltage without performing a removing work or a gas disposal for a withstand voltage test at site by supporting the ground side of lightning arrester element part to be insulated from a metal container, and installing a grounding switch on the ground side of the arrester element part. CONSTITUTION:For a withstand voltage test at site, a movable contact 19 connected with a main shaft 22 of a grounding switch 26 disposed at the external of a metal container 9 is driven by rotation the main shaft 22 to open it easily when a need of separation a lightening arrester occurs. In such an open circuit condition, a fixed contact 18 and the movable contact 19 are dissociated from each other on the ground side of an arrester element part 10, where the grounding of the arrester element part 10 is kept released. A predetermined insulation distance is secured between the arrester element part 10 and the metal container 9 of a ground potential, thereby a sufficient insulation performance to withstand if a test voltage is applied from the charging side can be provided.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Field of Industrial Application) The present invention has been improved so that voltage can be applied without removal work or gas treatment even during on-site withstand voltage tests. This relates to the lightning arrester.

(Prior Art) Recently, with the demand for larger capacity and smaller size of electric station equipment such as substations, circuit breakers, disconnectors, earthing switches, busbars connecting these devices, etc. have been replaced with SF6 gas, etc. Gas-insulated switchgear is used, which is housed in a metal container filled with an insulating gas.

Figure 4 shows a single-line diagram of a typical gas-insulated switchgear, and the line inlet is equipped with a lightning arrester 1 to protect the switchgear and transformer from abnormal voltages such as those caused by lightning. ing. Further, FIG. 5 shows an example in which the line portion is constructed by a gas insulated switchgear. That is, the connection from the overhead power transmission line is first received by the bushing 2, then passed through the disconnector 3 and the circuit breaker 4, and then connected to the main buses 7 and 8 via the disconnector 5.6. In this case, a lightning arrester 1 is usually provided near the bushing 2. Furthermore, the structure of the lightning arrester is shown in FIG. That is, a lightning arrester element section 10 made of a zinc oxide element or the like is housed in a metal container 9, and the container is further filled with SF6 gas 15 for insulation. Further, the lightning arrester element section 10 is connected to an adjacent gas insulated bus bar via a conductor 11, a contact 12, and a conductor 13.

When gas-insulated switchgear with this type of configuration is installed at a substation, a withstand voltage test is conducted on-site to confirm its electrical insulation performance before actual system operation begins. . This withstand voltage test involves applying a predetermined alternating current voltage for a predetermined period of time, and is also applied to the lightning arrester, which is a component of the gas-insulated switchgear. in this case,
A current will flow through the lightning arrester element 10, but in the conventional lightning arrester based on insulation reinforcement, the application time of the AC voltage is not so long, so it has the ability to withstand this. However, in recent years, with the remarkable progress of lightning arresters, emphasis on insulation has been reviewed, and attempts have been made to reduce the lightning impulse level and improve the economic efficiency of the switchgear as a whole.

(Problems to be Solved by the Invention) However, the conventional lightning arrester having the above configuration has the following problems to be solved. That is,
As a result of reducing the lightning impulse level of the arrester element, it is no longer possible to apply the AC voltage that was conventionally applied during on-site withstand voltage tests. It became necessary to disconnect the lightning arrester from the gas-insulated switchgear.

In order to cope with this, conventionally, as shown in FIG. 7, a disconnection bus bar 16 has been disposed between the bus bar 17 of the gas insulated switchgear and the lightning arrester 1. This is done before the withstanding voltage test.
After removing the manhole cover provided on the side of the disconnection bus 16 and removing the internal conductor, and applying an end treatment to withstand voltage, the manhole cover is attached and SF6 gas is injected into the inside. Since the inside of the disconnection bus bar 16 is electrically disconnected, even if a test voltage is applied from the bus source 2, no voltage is applied to the surge arrester 1. After the withstand voltage test, the disconnection bus bar 16 is returned to its original state and connected.

However, in the above method, in order to open the gas insulation part, gas treatment such as evacuation and gas filling must be performed each time, which not only takes a lot of time but also requires the removal of the conductor at the disconnection bus bar 16. Since reattachment requires work, the work process is complicated and requires careful attention to quality, such as not bringing foreign matter into the interior during work.

Furthermore, since gas insulation parts do not like moisture, this work was affected by the weather, which had a significant impact on the substation construction process.

The present invention was proposed in order to eliminate the above-mentioned drawbacks, and its purpose is to provide a lightning arrester that can apply a test voltage even during on-site withstand voltage tests without removing or gas treatment. It is about providing.

[Structure of the Invention] (Means for Solving the Problems) The lightning arrester of the present invention includes supporting the grounding side of the lightning arrester element portion insulated from the metal container, and installing a grounding switch on the grounding side of the lightning arrester element portion. It is characterized by:

(Function) According to the lightning arrester of the present invention, the lightning arrester element can be easily grounded or disconnected from the grounded state by operating the grounding switch attached to the grounding side of the lightning arrester element. Even during a withstand voltage test, it is possible to easily avoid applying a test voltage to the lightning arrester element.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 and 2. Incidentally, the same members as those of the conventional type shown in FIG. 6 are given the same reference numerals, and the description thereof will be omitted.

In the present embodiment, as shown in FIG. is provided.

Further, a movable contact 19 is disposed at a position facing the fixed side contact 18 so as to be movable toward and away from the movable contact 19 . This movable contactor 19 is connected to a grounding switch 2 disposed outside the metal container 9.
It is connected to the main shaft 22 via an insulating link 20 and a lever 21 provided in the main shaft 6. Furthermore, the movable contact 19
is configured to be grounded in the atmosphere via an insulated ground terminal 23.

In the lightning arrester of this embodiment having such a configuration, the separation work can be easily performed as described below. That is, when it becomes necessary to disconnect the lightning arrester during an on-site withstand voltage test, by rotating the main shaft 22 of the earthing switch 26 disposed outside the metal container 9, the movable contact connected thereto is removed. By driving the child 19 to the right in the figure, the open circuit state as shown in FIG. 2 can be easily achieved. In such an open circuit state, the fixed contact 18 and the movable contact 19 are separated from each other on the ground side of the arrester element 10, so that the arrester element 10 is disconnected from the ground. Furthermore, since a predetermined insulation distance is ensured between the lightning arrester element part 10 and the metal container 9 at ground potential, even if a test voltage is applied to the lightning arrester element part 10 from the charging side, it can withstand this sufficiently. It has good insulation performance.

This is because the entire arrester element section is insulated from the ground by creating an open circuit state, so no current flows into the element section even when a test voltage is applied.

In this way, according to this embodiment, the arrester element part 10 can be easily separated from the gas-insulated switchgear side without performing complicated work such as gas treatment and disassembly work as in the conventional case. The time required for withstanding voltage tests can be significantly shortened, the process is not affected by weather, and the initial insulation performance can be maintained. Furthermore, even if the on-site withstand voltage test voltage is applied to the gas-insulated switchgear side, the application to the lightning arrester element portion can be easily avoided.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and as shown in FIG. can get.

[Effects of the Invention] As described above, according to the present invention, the grounding side of the lightning arrester element is insulated and supported from the metal container, and a grounding switch is attached to the grounding side of the lightning arrester element, thereby improving on-site durability. It is possible to provide a lightning arrester to which a test voltage can be applied even during a voltage test without removal work or gas treatment.

[Brief explanation of drawings]

1 and 2 are sectional views showing one embodiment of the lightning arrester of the present invention, in which FIG. 1 shows the closed circuit state, FIG. 2 shows the open circuit state, and FIG. 3 shows the lightning arrester of the present invention. 4 is a single line diagram of a general gas insulated switchgear, FIG. 5 is a side view showing an example in which the line portion is configured by a gas insulated switchgear, and FIG. 6 is a sectional view showing another embodiment. 7 is a sectional view showing an example of the configuration of a conventional lightning arrester, and FIG. 7 is a side view showing an example of the configuration of a gas-insulated switchgear using the conventional lightning arrester. 1... Lightning arrester, 2... Bushing, 3... Disconnector, 4... Gas circuit breaker, 5, 6... Disconnector, 7, 8...
...Main bus bar, 9...Metal container, 10...Surge arrester element portion, 11...Conductor, 12...Contactor, 13...Conductor, 14...Insulating spacer, 15... SF6 gas,
16... Bus bar for disconnection, 17... Bus bar, 18...
- Fixed side contact, 19... Movable contact, 20... Link, 21... Lever, 22... Main shaft, 23...
Insulated ground terminal, 24... Electrode, 25... Insulated tube, 2
6...Earthing switch.

Claims (1)

[Claims] In a surge arrester used in gas-insulated switchgear, the ground side of the surge arrester element is insulated and supported from the metal container, and
A lightning arrester characterized in that a grounding switch is attached to the grounding side of the lightning arrester element section.