SU1403198A1 - Method of attenuating the field of synchronous machine with thyristor exciter - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase reliability by preventing the dangerous increase in the time of the floor damping due to a malfunction of the driver. In case of malfunctions in the thyristor driver of the synchronous machine 1, the current in the excitation winding 2 exceeds the value 21 "o" - The current is measured by sensor 6 and compared in block 7 with the maximum allowable value. When the current exceeds this value, the automatic switch-off of field 3 is disconnected by opening the contacts of its main electric circuit including the excitation winding 2 and thyristor converter 4 of the exciter of the synchronous machine 1. The fact of opening of the contacts of the main electric circuit is fixed with the help of controlling block contacts. After the time delay has elapsed, the signal from the output of the time delay unit 8 is fed to the control pulse picker 5, which removes the control pulses from the thyristors of the converter 4. 1 sludge. with (L

Description

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The invention relates to electrical engineering, in particular to methods for damping the floor of a synchronous machine with a thyristor exciter.

The aim of the invention is to increase reliability by preventing the dangerous increase in the time of field quenching due to a malfunction of the driver.

The drawing shows a block diagram of a device that implements the proposed method.

A device for carrying out the method according to the invention comprises a synchronous machine 1, an excitation winding 2 connected to an automatic field quenching device 3, an exciter thyristor converter 4 connected to an inverter thyristor control pulse pickup unit 5, an excitation current magnitude sensor 6 connected to the excitation winding circuit connected to block 7 comparing the magnitude of the excitation current with a predetermined setpoint and to block 8 of the time delay.

The device works as follows.

The current is measured by sensor 6 and compared in block 7 with a maximum permissible value of 2.2 1 -5 to 4400 A. When the current exceeds this value, the automatic 3-field switch-off is turned off. In the process of switching off this automaton, the contacts of its main electric circuit, including the excitation winding 2 and the thyristor converter 4 of the exciter of the synchronous machine 1, open, and then the arc is extinguished in the arc arrest of this automaton. The fact of the opening of the contacts of the main electric circuit is fixed by means of the control block contacts, the signal of the closure of which is fed to the input of the block 8 time delay. After a time delay t 0.2 s, the signal from the output of this block is fed to the control pulse pickup unit 5, which extracts the control pulses from the thyristors of the converter 4. As a result of the pulse removal, the excitation force caused by a malfunction of the automatic control regulator or control system ceases thyristors, and the process of arc extinction in the arc-suppressing grid of the field 3 automaton is continued with the average value of the rectified voltage of the thyristor converter 4 of the exciter, 0, in terms of maintaining the conduction of the excitation current by the same thyristors of the converter 4 for the entire subsequent time of field hardening. The exposure time field in block 8 is selected from the permissibility condition for overload

the current of the thyristors remaining in the conducting state, and the fuses connected in the thyristor converter in series with these thyristors.

Thus, as a result of the cessation of the action of the excitation voltage forcing caused by a malfunction of the automatic excitation controller or the thyristor control system and contributing to a significant increase in the time of field synchronization of the synchronous machine,

the damping is carried out only under the action of the voltage provided by the machine for extinguishing the floor, and there is no danger of an unacceptable increase in the absorption time.

Using the proposed method

allows you to prevent significant accidental damage to the equipment of the synchronous machine and its exciter, which can occur at power plants due to an unacceptable increase in the time of blanking the floor.

Claims (1)

Invention Formula Method for shaking the floor of a synchronous machine with a thyristor exciter with a block control, based on measuring the field current, comparing this value with a predetermined setpoint and when this value exceeds a predetermined setpoint, switching off the automatic field shutdown, characterized in that, in order to increase reliability by preventing a dangerous increase in the field extinguishing time due to a malfunction of the exciter, they record the fact of the opening of the contacts of the main circuit of the automatic shutdown field, after which with a given time delay they form a signal to remove the thyristor control pulses.