SU148844A1 - A device for temporarily shunting one of the bridges of a multi-bridge converter - Google Patents

Description

Basically auth. St. No. 144225 described a device for temporarily shunting one of the bridges of the multi-bridge converter of engineer Gordin B.I., equipped with an arcing chamber, in which the arc formed by the ashnarat contacts is exposed to a flow of gas or liquid.

The present additional invention develops the basic invention, making it possible to re-bypass the bridge in the event that the valves are not successfully fired during the process of its de-shunting. For this purpose, a pneumatic drive is used in the device, holding the contacts of the arc chamber in the open state for a predetermined period of time, after which they are automatically closed by means of a spring. In series with the contacts of the arc chamber, a separator can be switched on, the impulse for opening of which is supplied only in the presence of current in the shunt valve circuit. The arc chamber can be connected to that of the poles of the bridge, which has a lower potential relative to the ground.

FIG. 1 shows the electrical circuit of the multi-bridge converter (only two bridges are conventionally shown in the diagram) with the proposed device; in fig. 2 is a schematic diagram of an air shunt apparatus.

On the electrical diagram, the label}: / - transformers, 2 - working valves assembled according to bridge circuit, 3-shunt valves, 4-shunt devices, 5 - disconnectors, 6 - separators, 7 - arc chambers. The sequence of the inclusion of the elements of the scheme described in the main author. St. No. 144225.

No. 148844-2B development of the main application shunt apparatus 4 has two pairs of switching elements connected in series, the separator 6 and the arc chamber 7. The bridge is put into operation after the shunt is made by opening the contacts of the arc chamber 7 with blowing them with compressed air and if the valve does not come on, re-closes the contacts. The separator 6 and the arc chamber 7 are supplied with a pneumatic actuator. In FIG. 2, the design of the arc chamber 7 is made of an insulating cylinder 8, inside of which there is a spring-loaded tubular contact 9 provided with a piston. The contact 9 moves in the direction of the cylinder of the flange 10, which also serves as a conductor. From the movable contact 9, the current passes to the fixed contact, fixed in the lower flange 11, then to the separator knife 6, the fixed contact 12 of the separator located on the column of insulators 13.

When voltage is applied to the electromagnet 14, a system of pneumatic valves 15 is activated, supplying compressed air from the reservoir 16 through the insulating cylinder 17 to the arc chamber 7.

Compressed air, acting on the piston of contact 5, raises it. In the place of opening of the contacts, a direct current arc is formed, which under the action of compressed air moves inside the contacts and is subjected to intensive blowing there, which causes an increase in voltage on the arc, in order to improve the ignition condition of the shunt valve.

After stopping the supply of compressed air, contact 9 is lowered by the action of a spring, i.e. the contacts of the arc chamber close. The separator 6 is a knife actuated by the piston 18 of the pneumatic actuator 19. The separator 6 is disconnected when voltage is applied to the electromagnet 20, which, through a system of valves 21, supplies compressed air from the reservoir 16 through the insulating tube 22 to the actuator 19. The piston 18 Moving to the right, raises the knife, making the separator shut off. The impulse to open the separator is given only in the presence of current in the circuit of the shunt valve. To disconnect the separator, it is necessary to apply a voltage to the electromagnet 23.

In the multi-bridge converter circuit, the reference insulation of one of the contacts of the shunt apparatus is under a lower voltage than the reference insulation of the other contact.

Taking into account that the support insulation of the arc chamber is more complex and expensive, it is proposed to install a shunt apparatus in the converter circuit so that the arc chamber is connected to that of the poles of the bridge, which has a lower potential relative to the ground. In this case, the columns of the arc chamber and the fixed contact of the separator can be manufactured with different levels of insulation, which allows cost savings of the insulating structures.

Subject invention

Claims (3)

1. A device for temporarily shunting one of the bridges of a multi-bridge converter, for example, at substations of high-voltage DC transmissions, made in the form of a switching device, according to the author. St. No. 144225, characterized in that, with the Purpose of re-shunting the bridge in case of unsuccessful valve ignition. In the process of its de-shunting, a pneumatic drive is used, keeping the contacts of the arc chamber in the open state for a predetermined period of time, after which they are automatically are closed with a spring. 2. The device according to claim 1, characterized in that a separator is connected in series with the contacts of the arc chamber, the pulse for opening is supplied only if there is current in the shunt valve circuit. 3. The device according to paragraphs. 1 and 2, characterized in that the arc chamber is connected to that of the poles of the bridge, which has a lower potential relative to the earth.