JPH0564027B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a thyristor valve for AC/DC conversion in DC power transmission or interconnection between different frequency power systems, and particularly relates to a thyristor valve that is optimal in terms of earthquake resistance and insulation structure. .

[Technical Background of the Invention and Problems Therewith] Air-insulated thyristor valves for AC/DC conversion in DC power transmission or inter-frequency interconnection, etc., are becoming taller and larger with the recent trend toward higher voltages and larger currents. Furthermore, in order to reduce the construction cost of the valve hall in which the thyristor valve is installed, thyristor valves are becoming increasingly high-rise in order to minimize the floor area of the valve hall. Therefore, there is a need to manufacture a thyristor valve that is compact and easy to maintain and inspect, which is constructed of an insulating column that is inexpensive and has sufficient strength.

Air-insulated thyristor valves are made of reinforced plastic (hereinafter simply referred to as "reinforced plastic", which is about 10 times stronger than insulators due to its electrical insulation and the above-mentioned strength).
FRP) is used.

A conventional thyristor valve will be explained below with reference to FIGS. 1 to 3. The thyristor valve 7 is a thyristor that houses a thyristor stack 2 in which a plurality of thyristor elements 1 are connected in series and parallel as shown in FIG. As shown in FIGS. 2 and 3, modules 6 are stacked and connected in several stages using insulating columns 8 made of FRP. In the figure, 5 is a light guide that sends optical signals to the thyristor element 1, 9 is a module support plate protruding from the FRP insulation column 8, 10 is the upper and lower frame of the thyristor bulb, 11 is the lower base, and 12 is the thyristor bulb 7 from the ground. This is an FRP insulating column that provides insulation support.

Conventional FRP insulating columns 8 and 12 do not have creases to provide creepage distance like insulators, so there is a problem that the height of the thyristor valve increases, which reduces the insulation reliability of the thyristor valve and reduces its seismic strength. will also have a major impact.

[Object of the Invention] It is an object of the present invention to solve the above-mentioned problems and provide a thyristor valve that is inexpensive, has high reliability in terms of strength and insulation, and is easy to maintain and inspect.

[Summary of the invention] The present invention provides insulating support for a thyristor valve.
The purpose is to add pleats to the outside surface of the FRP strut and to fill the inside with SF ₆ gas.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 4 and 5. The FRP column 8 is an insulating cylinder formed by wrapping glass cloth and epoxy resin as a binder around a circular mold. After the mold is removed, flanges 13 are attached to both ends and the required number of thyristor modules 6 are installed in the middle part. It is constructed by attaching a mounting plate 9 for mounting. Since the surface of the FRP support column 8 has irregularities due to machining, it is usually finished by shaving the surface, but by shaving the surface into pleats 14 during the final shaving, the creepage distance can be increased. However, the inner surface of the support column 8 cannot be pleated in order to remove the mold, and since it is long, it cannot be cut down to make pleats. Therefore, a structure that can seal the flanges 13 at both ends is attached to an FRP insulating column, and an outlet pipe 15 attached to the flanges 13 is installed.
The SF ₆ gas 16 is sealed by filling a gas with a higher insulating property such as SF ₆ gas, and then closing the outlet pipe 15 with a spout or the like.

Regarding creepage insulation between SF ₆ gas and FRP insulation columns, the creepage distance can be made extremely short compared to air. However, although the creeping flashover voltage differs due to subtle changes in the surface of the insulator or the opposing shapes of the flanges 13 at both ends, the creeping insulation strength of SF ₆ gas and air under normal pressure is expressed as shown in FIG. Since thyristor valves are normally placed in a clean environment with a dust-proof structure that controls temperature and humidity, the creepage distance of the insulator can be shorter than under normal conditions. The maximum processing limit for the creepage distance due to folds on the surface of the FRP insulating support is approximately 1.5 to 2 times the height. Furthermore, as can be seen from FIG. 5, SF ₆ gas has an insulating strength at least twice that of air at approximately 1 Kg/cm ² ads. Therefore, by taking into account the good environmental conditions in which the thyristor valve is placed, the creepage distance due to the pleats should be 1.5 to 2 times the height, and the gas pressure should be 1 to 1.5 Kg/cm ² ads as shown in Figure 5. There is sufficient coordination. In addition, since the pressure is almost atmospheric, sealing is simple and there is little chance of leakage, resulting in improved reliability.

[Effects of the invention] As mentioned above, the creepage distance can be increased by adding pleats to the support of the thyristor valve and using an FRP insulating column that is filled with an insulating gas such as SF ₆ gas. The height of the thyristor valve can be lowered and the insulation properties can be improved. Furthermore, since the height of the thyristor valve is reduced, the seismic strength is dramatically improved, and maintenance and inspection such as replacing the thyristor module can be easily performed, leading to improved reliability.

[Brief explanation of the drawing]

Figure 1 is an internal circuit diagram of a typical thyristor module, Figure 2 is a sectional view taken along line A-A in Figure 3 showing the configuration of the thyristor valve, Figure 3 is a front view of the thyristor valve, and Figure 4 is the invention of the present invention. Fig. 5 is a diagram showing the structure of an FRP insulating column according to Fig. 5, and Fig. 5 is a diagram showing the insulation strength depending on the pressure of SF ₆ gas and air. 1... Thyristor element, 2... Thyristor stack, 3... Anode reactor, 4... Voltage dividing circuit, 5... Light guide, 6... Thyristor module, 7... Thyristor valve, 8... FRP
Insulating support column, 9...Module support plate, 10...Valve upper and lower frames, 11...Valve lower base,
12... FRP insulating support between ground, 13... Flange, 14... Fold, 15... Outlet pipe, 16...
…SF ₆ gas.

Claims (1)

[Scope of Claims] 1. A thyristor valve configured by stacking a thyristor module containing a plurality of thyristor elements and their associated circuits such as capacitors, resistors, reactors, etc. in several stages using insulating supports,
The insulating support is characterized by using a cylindrical reinforced plastic (FRP) insulating column which has pleats on the external surface to provide a creepage distance and is filled with an insulating gas such as SF ₆ gas inside. thyristor valve. 2. The creepage distance due to pleats should be 1.5 to 2 times the height of the FRP insulating column, and the pressure of SF ₆ gas should be 1 to 1.5 times.
The thyristor valve according to claim 1, characterized in that an FRP insulating column with a weight of Kg/cm ² ABS is used.