JPH0237208Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a reduced type switchgear with an improved wiring structure.

B. Prior Art There is a reduced type switchgear in which a vacuum circuit breaker, a disconnector, etc. are housed in a sealed tank, and the tank is filled with insulating gas. This reduces the distance between each device by filling the tank with insulating gas.
This also aims to reduce the size of the opening/closing device.

A wiring diagram of a conventional reduced type switchgear is shown in FIG. The figure shows a part of the reduced type switchgear, where 1 is a tank, 2 is a disconnector, and 3 is a vacuum circuit breaker. In other words, the power supply (not shown), the vacuum circuit breaker 3, the disconnector 2, and the load (not shown) are connected to the power supply bus 6,
They are connected by a connection bus 5 and a load bus 4. The connection busbar 5 is grounded by a second grounding wire 8 via a grounding switch 12 and an insulated terminal 7 attached to the tank 1, respectively. In addition, in order to perform a vacuum test of the vacuum circuit breaker 3, a vacuum detecting section 9 is provided on the first grounding wire 11 that connects the load bus 4 to the ground via the insulated terminal 10. Outside the tank 1, an alarm (not shown) is provided to the first grounding wire 11 via a current detector such as a current transformer.

When performing maintenance inspection of the vacuum circuit breaker 3, open the vacuum circuit breaker 3, then open the disconnector 2, close the grounding switch 12, and transfer the charging current remaining in the vacuum circuit breaker 3 to the second ground. Escape to the earth via line 8. In this way, maintenance and inspection can be carried out safely.

When checking the degree of vacuum of the vacuum circuit breaker 3, open the vacuum circuit breaker 3 and the disconnector 2, close the grounding switch 12 once, then open the grounding switch 12 and close the disconnector 2. In the case of vacuum deterioration, the withstand voltage between the electrodes in the vacuum circuit breaker 3 drops to nearly 100V due to the discharge characteristics of the vacuum circuit breaker, which causes a discharge between the electrodes and a voltage appears on the load bus 4 side. Therefore, a discharge current flows through the degree of vacuum detection section 9, and the alarm device issues an alarm.

C. Problems to be solved by the invention However, the insulated terminal 7 used to connect the earthing switch 12 and the earth, and the thick-rimmed terminal 10 used to connect the vacuum level detection section 9 and the earth are connected to a tank. Since three parts are separately attached to each part, this hinders miniaturization of the switchgear and increases the number of parts.

Therefore, an object of the present invention is to reduce the number of insulated terminals and provide a reduced-sized switchgear that can be further downsized.

D. Means and action for solving the problem The present invention eliminates the direct connection of the other end of the first grounding wire to the outside of the tank, and the grounding at the second grounding wire connected to the ground. By connecting the other end of the first grounding wire between the switch and the tank, the portion of the grounding wire led outside the tank is halved.

E. Embodiments The present invention will be described below based on embodiments shown in the drawings. In addition, since the present invention is a partial improvement of the conventional reduced-type opening/closing device described above, the same parts will be given the same reference numerals and explanations will be omitted, and only the different parts will be explained.

An embodiment of the present invention is shown in FIG. As shown,
A degree of vacuum detection section 9 is interposed, and one end of the first grounding wire 11a is connected to the load bus 4, and the other end of the first grounding wire 11a is connected to the second grounding wire 8, respectively. The first grounding wire 11a is connected to the second grounding wire 8 between the grounding switch 12 and the insulated terminal 7.

Outside the tank 1, an alarm (not shown) is provided below the second grounding wire 8 via a current detector such as a current transformer, as in the conventional case.

Next, the operation of such a reduced type switchgear will be explained.

Since the grounding switch 12 is open when the disconnector 2 and the vacuum circuit breaker 3 are closed, the degree of vacuum detection section 9 is grounded via the first grounding wire 11a and the second grounding wire 8.

On the other hand, when performing various tests, such as main circuit resistance measurements, insulation resistance tests, or device operation confirmation tests, open the vacuum circuit breaker 3 and the disconnector 2, and
The earthing switch 12 is closed and various tests are performed.

Next, when the vacuum circuit breaker 3 is opened, the disconnector 2 and the earthing switch 12 are closed, and the earthing switch 12 is opened, only when the vacuum circuit breaker 3 has deteriorated due to vacuum, the load bus 4 A voltage appears on the side, and a discharge current flows to the ground via the first grounding wire 11a and the second grounding wire 8. Therefore, current also flows through the alarm device and an alarm is issued.

With the above configuration, only three insulated terminals are required compared to the conventional six, and the reduced-sized switchgear can be made more compact.

FIG. 2 shows the vicinity of the insulated terminal mounting portion in the reduced-sized switchgear according to the present invention.

A mounting hole 1a is drilled in the tank 1, and the mounting hole 1a
An insulated terminal 7 is fitted through an O-ring 13 for preventing gas leakage and fixed with a bolt 14. The insulated terminal 7 is a conductor 15 molded with epoxy resin, and a second ground wire 8 is connected to both ends of the conductor 15 by bolts 16, respectively.

F. Effect of the invention As explained above, according to the invention, the other end of the first grounding wire, which should be connected to the earth, is connected inside the tank to the second grounding wire led outside the tank and connected to the earth. Therefore, there is no need for an insulated terminal to lead the first grounding wire to the outside of the tank, and the cost is low because the number of parts is small and no processing or assembly work is required. In addition, by reducing the number of insulated terminals, the size can be reduced.
The rate of gas leakage from the insulated terminal portion is reduced and reliability against leakage is improved.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 relate to an embodiment of the reduced type switchgear according to the present invention, Fig. 1 is a wiring diagram, Fig. 2 is a sectional view showing the vicinity of the insulated terminal, and Fig. 3 is a conventional reduced type switchgear. FIG. 3 is a wiring diagram of the device. 1... Tank, 2... Disconnector, 3... Vacuum breaker, 4... Load bus, 5... Connection bus, 6... Power bus, 8... Second grounding wire, 9... Vacuum level detection Part, 11a...first grounding wire, 12...grounding switch.

Claims (1)

[Scope of utility model registration request] A disconnect switch, a vacuum circuit breaker, a grounding switch, a vacuum detection unit, etc. are housed in a sealed tank, and the disconnect switch is connected to a load via a load bus, and the vacuum circuit breaker is connected to a power bus. the disconnector and the vacuum circuit breaker are connected via a connection busbar, one end of the first grounding wire provided with the degree of vacuum detection section is connected to the load busbar, and the other end is connected to the load busbar. A reduced type switch whose end is connected to the ground outside the tank, one end of which is connected to the connection bus bar, and the other end is connected to the ground outside the tank. A reduced type switchgear, characterized in that the other end of the first grounding wire is connected to the second grounding wire located between the grounding switch and the tank.