JPH04126321A - Switching device for underground substation - Google Patents

Abstract

PURPOSE:To improve safety by using a nonflammable fluid such as perfluorocarbon compound as a working fluid of a hydraulic operating device. CONSTITUTION:A hydraulic operating device 1 is composed of an operating cylinder 9 to which an operating piston 10 connected to a rod 10a is inserted in a manner capable of sliding, a control valve 13 for controlling motion of the operating cylinder 9 and a fluid pump 11. In this case, a perfluorocarbon compound, for example, as a nonflammable-fluid is used. As a result, even if leakage of the operating fluid occurs from piping and seal parts, there is few in danger of firing, and also it is free from care for breakage of a gas insulated switching device and leakage of an insulation medium, safety is then improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to switching equipment for underground substations, and more particularly to switching equipment for underground substations in which switching parts such as circuit breakers are opened and closed by hydraulic operating devices.

[Background Art] Recently, substations are increasingly being constructed as underground substations due to the soaring price of land in and around cities. This underground substation employs a gas-insulated switchgear that uses an insulating gas such as SFs gas as an insulating medium, thereby reducing the installation area.

Moreover, hydraulic operating devices and spring operating devices have come to be used as operating devices for opening and closing switching parts such as circuit breakers in gas-insulated switchgears. This is because when using an air operating device that uses compressed air as its drive source, maintenance and inspection of auxiliary equipment such as a compressor that generates compressed air is required. This is because they are being transferred to bone operating devices. especially,
Buffer-type gas circuit breakers that require a large driving force employ a hydraulic operating device, and this type of hydraulic operating device is introduced, for example, in Japanese Patent Publication No. 62-58092.

This hydraulic operating device uses mineral oil as the working fluid,
The working pressure of the working fluid was high, around 300 bar.

[Problems to be Solved by the Invention] However, since conventional hydraulic operating devices for underground power plant switchgear use mineral oil as their working fluid, there is no possibility of leakage from mineral oil piping or seals pressurized to about 300 bar. When a spill occurs, its flash point is 100~
As the temperature was as low as 160 degrees Celsius, there was a risk of fire. Furthermore, if the mineral oil turns into a mist, it will cause an explosion and fire accident, which will damage the gas-insulated switchgear and cause M! If the surrounding media leaks, there is a risk of an oxygen deficiency accident inside the underground substation or in the adjacent underground mall.

SUMMARY OF THE INVENTION An object of the present invention is to provide a switchgear for an underground substation that has a hydraulic operating device that prevents the risk of fire and improves safety.

[Means for Solving the Problems] In order to achieve the above object, the present invention uses a nonflammable fluid such as a perfluorocarbon compound or a flame retardant fluid such as silicone oil as the working fluid of a hydraulic operating device. It is characterized by

[Function] Since the underground substation switchgear according to the present invention has the above-described configuration, even if the working fluid should leak out,
It is possible to prevent the occurrence of a fire and the accompanying explosion of the gas insulated switchgear, thereby further improving safety.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the main parts of a switchgear for an underground power plant according to an embodiment of the present invention.

The gas insulated switchgear [8, which constitutes the switchgear for underground substations, is constructed by enclosing an insulating medium such as SF or gas in a gas container 2, and supporting the main circuit conductor 4 with an insulator 3. An opening/closing part 7 such as a circuit breaker is constructed electrically in series in the middle of the main circuit conductor 4, and this opening/closing part 7 has a fixed contact 5 and a movable contact 6. This movable contactor 6 maintains the airtightness of the gas container 2 and is connected to the hydraulic operating device 1 by means of a rod 10a electrically insulated from the main circuit conductor 4.
The opening/closing operation is performed by this hydraulic operating device 1.

Hydraulic operating device! 1 includes an operating cylinder 9 into which an operating piston 10 coupled to a rod 10a is slidably fitted, a control valve 13 that controls the operation of the operating cylinder 9, a fluid pump 11, and a fluid pump 11. It consists of an accumulator 12 for storing high-pressure operating fluid, and pilot valves for opening and closing, etc. (not shown).

The inside of the operating cylinder 9 is divided by the operating piston 10 into a rond side fluid chamber 9a and a control valve side fluid chamber 9b, and the rond side fluid chamber 9a is always in communication with the accumulator 12, while the control valve side fluid chamber 9b The control valve 13 connects the fluid pump 11 via the low pressure pipe 21 and the high pressure pipe 20.
It is configured so that it is alternately connected to the accumulator 12 via.

The fluid chamber 13a of the control valve 13 is controlled by a pilot valve (not shown) to supply and discharge high-pressure working fluid that acts as a driving force to the right in the drawing with respect to the spool 14, and is connected to the control valve side fluid chamber 9b described above. Switch.

Further, the fluid pump 11 includes a fluid container 15 and a motor 17 that operates the pump 16, and the fluid container 15 has a sealed structure.

Here, a nonflammable fluid such as a perfluorocarbon compound is used as the working fluid of the hydraulic operating device.

This figure corresponds to the open state of the opening/closing part 7, and the control valve 1 with the Rondo side fluid chamber 9a and the valve seat 13c closed.
The fluid chamber 13b of No. 3 is connected to the accumulator 12, and a high-pressure working fluid acts thereon.

A downward force is applied to the operating piston 10 to hold the movable contact 6 in the open position via the rod 10a.

In this state, when a circuit closing command is given and a circuit closing pilot valve (not shown) is activated and high-pressure working fluid flows into the fluid chamber 13a, the spool 14 is driven to the right. As a result, the valve seat 13d is closed and the valve seat 13c is closed.
is opened, and the control valve side fluid chamber 9b is connected to the accumulator 12 via the valve seat 13c. A rod 10a is connected to the operating piston 10, and since there is a difference in area between the upper and lower pressure-receiving surfaces, the movable contact 6 receives an upward force as a whole through the rod 10a. is driven to create a closed circuit state.

On the other hand, in the circuit opening operation, the high pressure working fluid in the fluid chamber 13a is discharged by a circuit opening pilot valve (not shown), and the spool 1
4 to the left to bring it into the state shown, the control valve side fluid chamber 9b is communicated with the fluid pump 11 via the valve seat 13d and the low pressure pipe 21, and the operating piston 1o is driven by the working fluid in the rod side fluid chamber 9a. This is done by driving it downward.

As mentioned above, since a nonflammable fluid is used as the working fluid in this hydraulic operating device, even if the working fluid leaks from the piping or seals.

A highly safe underground substation switchgear with less risk of fire and no risk of damaging the gas insulated switchgear and leaking the insulating medium can be obtained. In addition, transformers are located in underground substations connected to gas-insulated switchgear.
Recently, perfluorocarbon compounds and S are used as insulating media.
F. A non-flammable transformer using a composite insulation method using gas has been devised, and if a perfluorocarbon compound is used as the non-flammable fluid, the same fluid will be used for the switchgear and the transformer, making it economically viable. This is advantageous and also facilitates maintenance.

Further, as another embodiment of the present invention, a flame-retardant fluid, such as silicone oil or hydrocarbon oil, may be used as the working fluid of the hydraulic operating device, and by this, almost the same effect as in the previous embodiment can be obtained. be able to.

FIG. 3 is a longitudinal cross-sectional view showing a main part of a switchgear for an underground substation according to a different embodiment of the present invention, that is, the fluid pump 11 of FIG. 1.

As can be seen from a comparison with FIG. 2, which shows a conventional fluid pump, an intake/exhaust port 19 is formed at the top of the conventional fluid container 15, but in FIG. An auxiliary container 23 is added to form the fluid container 15 with a closed structure.

When a perfluorocarbon compound is used as a working fluid, its boiling point is around 100"C and it evaporates easily.
If the intake and exhaust ports 19 are formed as in the past, the amount of fluid may decrease due to evaporation, and the evaporated gas may cause oxygen deficiency in the underground substation. However, as shown in Figs. 1 and 3, By making the container 15 a sealed structure,
This can be prevented. In particular, if an auxiliary container 23 is added as shown in FIG. 3, the fluid container itself may be fabricated using a conventional one. Furthermore, when the level of the working fluid in the fluid container 15 changes due to the movement of the working fluid during opening/closing operations or changes in ambient temperature, and the pressure in the fluid container 15 changes, for example, the pressure in the fluid container 15 increases by Since the flow rate from the low pressure piping 21 shown in the figure is restricted, the opening/closing operation characteristics are adversely affected, but by adding the auxiliary container 23 as shown in FIG. Opening/closing operation characteristics can be obtained.

FIG. 4 is a longitudinal sectional view showing a fluid pump 11 that is further improved in the above-mentioned respects. In this embodiment, an elastic member 24 such as a bellows whose upper end is sealed is provided on the upper part of the fluid container 15, and as the pressure inside the fluid container 15 increases, the elastic member 24 extends in the axial direction to increase the volume inside the fluid container 15. It has a closed structure that allows for expansion. At this time, the expansion and contraction of the expansion and contraction member 24 in the axial direction is as follows.

It is guided by a guide member 25.

According to this embodiment, the extensible member 24 operates more sensitively following pressure fluctuations within the fluid container 15, so that pressure fluctuations can be suppressed and stable opening/closing operation characteristics can be obtained. 1. In this embodiment, the extensible member 24 that expands and contracts in the axial direction is used, but it is sufficient to provide a responsive member that increases or decreases the volume of the fluid container 15 in response to pressure fluctuations within the fluid container 15, and the present invention is not limited to this. It's not a thing.

[Effects of the Invention] As explained above, the present invention uses a nonflammable fluid or a flame retardant fluid as the working fluid of a hydraulic operating device used as a switchgear for an underground substation, so even if the fluid leaks out, a fire will not occur. The present invention is compatible with gas-insulated switchgear suitable for underground substations, and can be made into a safer underground substation switchgear without causing an explosion.

[Brief explanation of the drawing]

FIG. 1 shows an underground substation switch II according to an embodiment of the present invention.
2 is a longitudinal sectional view showing the main parts of the device, FIG. 2 is a longitudinal sectional view showing a conventional fluid pump, and FIGS. 3 and 4 are fluid pumps for switching equipment for underground substations according to other different embodiments of the present invention. FIG. 1... Hydraulic operating device, 5... Fixed contact, 6... Movable contact, 7... Opening/closing part, 9... Operating cylinder, 10... Operating piston, 11... Fluid pump, 12...
・Accumulator, 13...Control valve, 15...
・Fluid container, 23... Auxiliary container, 24...
・Extensible member. Figure 2 Figure 2 Figure 2

Claims (1)

[Claims] 1. A hydraulic operating device that generates driving force by applying pressurized operating fluid from a fluid pump to an operating piston slidably disposed within an operating cylinder; 1. A switchgear for an underground substation having a switching part that is opened and closed by driving force, characterized in that a nonflammable fluid is used as the operating fluid. 2. A hydraulic operating device that generates driving force by applying pressurized operating fluid from a fluid pump to an operating piston slidably disposed within an operating cylinder, and an opening/closing operation using the driving force of this hydraulic operating device. 1. A switchgear for an underground substation having a switching part for an underground substation, characterized in that a flame-retardant fluid is used as the operating fluid. 3. The switchgear for an underground substation according to claim 1 or 2, wherein the fluid pump has a fluid container containing the operating fluid, and the fluid container has a sealed structure. 4. The switchgear for an underground substation according to claim 3, wherein the fluid container is provided with an expandable member that expands and contracts so that its internal volume can be increased or decreased.