SU1624594A1 - Device for protection of reversible thyristor converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used to protect reverse thyristor converters, in particular, to control electric drives. The purpose of the invention is to simplify the device. The device contains auxiliary windings on equalizing reactors connected in series with each other and connected to the coil of an electromagnetic relay. During the breakdown of any thyristor, the alternating component of the current of the equalizing reactors increases and, accordingly, the voltage on the auxiliary windings, which causes the relay 14 to trip and switch 2 off. 1 sludge.

Description

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The invention relates to electrical engineering and can be used, in particular, in direct current thyristor electric drives.

The purpose of the invention is to simplify the device for protecting a reversible thyristor converter.

The drawing shows a diagram of a reverse thyristor converter with a device for protection.

The armature of the electric motor 1 is connected to the output of a reversible thyristor converter made in a three-phase zero circuit. The controlled switch 2 is connected between the input of the reversible thyristor converter and the mains supply terminals. Thyristors 3-5 form the anode and thyristors 6-8 - the cathode group. connected in series between the combined anodes and the combined cathodes of the respective groups of thyristors; To the common point of equalization reactors 9-10, a smoothing throttle clamp 11 is connected, sec The second terminal is connected to the main circuit of the electric motor 1. The equalizing reactors 9 and 10 respectively have auxiliary windings 12 and 13. The beginnings of which are combined, and the ends are connected to the coil terminals of the electromagnetic relay 14, the contacts of which are connected to the disconnecting input of the controlled switch 2

The device works as follows.

During normal operation, the thyristors 3-8 surge reactors 9-10 operate with DC saturation caused by the DC component of the rectified current, and in the auxiliary circuits 12-13 surge reactors 9-10, the variable component signals are small according to the rectification scheme used. Since the signals of the auxiliary windings 12-13 are turned on and are low, the resulting circuit voltage level is insufficient

to trigger relay 14. In the breakdown of at least one thyristor from any group in the corresponding auxiliary winding of the surge reactor, despite its operation mode with bias,

the voltage level of the variable component increases dramatically, which leads to a sharp increase in the resulting voltage of the circuit, which includes the coil of the electromagnetic relay 14. This

leads to the triggering of relay 14, the formation of a signal at the input of the controlled switch 2 and its disconnection, as a result of which the supply voltage from the thyristors 3-8 is removed. Similarly, the device works in case of emergency short-circuit of the thyristor in any thyristor group.

Claims (1)

The invention of the device to protect the reverse thyristor converter, made on a three-phase zero circuit with two equalizing reactors connected in series between the combined anodes and the combined cathodes corresponding groups of thyristors, containing two auxiliary windings and an electromagnetic relay, the contacts of which are connected to the disconnecting input of a controlled switch, characterized by the fact that, in order to simplify the device, the auxiliary windings are designed to be placed on the respective equalization reactors, the beginnings of the auxiliary windings are combined, and the ends are connected to the coil terminals of the electromagnetic relay, wherein the controlled switch is designed to be connected between the input of a reversible thyristor converter and the terminals of the supply network.