JPS5820531B2 - Kaijisou Shitsukenshitsusouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a field loss detection device for a synchronous generator operated with an automatic voltage regulator.

Recently, with the increase in electricity demand, the capacity of power plants has increased, and the capacity of a single generator has also increased.The impact of a generator accident on the grid becomes greater, and greater reliability is required of generator protection devices. It's starting to look like this.

Conventionally, to detect field loss in synchronous generators, a distance relay type field loss relay was used that detects impedance changes seen at the generator terminals, but this has the risk of malfunctioning due to system failures, etc. .

This invention was made in view of these circumstances, and provides a field loss detection device that can reliably detect field loss by combining a field loss relay, a reactive power relay, and a low voltage relay. The purpose is to provide

An embodiment of the present invention will be described below with reference to the drawings.

Fig. 1 shows an outline of the device according to the invention, in which G is a synchronous generator, the output voltage of which is supplied in parallel to power grid lines L and L through a power transformer TR and a breaker CB. It is configured.

40 is a conventional field loss relay that detects the impedance seen at the generator terminal, and 57 is a reactive power relay that detects the "1 lead I + lag + 1 power factor" of the generator G output.
Both relays 40, 57 respond to the amount of electricity taken out via the current transformer CT and the lower transformer PT1.

27 detects the terminal voltage of the generator G at the voltage transformer PT11 and a half, and this terminal voltage is a constant value, for example, 9 of the rated voltage.
This is a low voltage relay that operates when the voltage is below 0.

EX is an exciter that excites the field winding F of the generator G, which includes a field regulator 70E and an Ambridyne AMP.
is connected.

AVR is an automatic voltage regulator that detects the terminal voltage of the generator G from the voltage transformer PT2t and brings it close to the reference value of the reference voltage setting device 90R. Ambridyne AM from Koyori
This is done so that P is controlled.

The control circuit of the field loss detection device having such a configuration is the second control circuit.
This is done as shown in the figure.

That is, the normally open auxiliary contact 52 of the parallel breaker CB between the control buses P and N, the contacts 43-90 of the opening/closing auxiliary relay in which the automatic voltage regulator AVR is used, and the reference voltage setting value of the reference voltage setting device 9OR. Limit switch 90Rn that closes when set to more than a certain value, for example 95 or more.
, “Reactive power relay 5 that closes when a leading 1 power factor is detected.
7 contact 57LD, output contact 2 of the low voltage relay 27
7a1 A series circuit of the trip coil 52T of the parallel breaker is connected.

The operation of the apparatus of the invention constructed as described above will be described below.

It is known that when a general synchronous generator G is connected in parallel to power grid lines and the field is lost during operation, the voltage at the generator terminals will drop by a factor of 90 or less.

Under normal operating conditions, the automatic voltage regulator AVR is operated in order to improve system stability, and the reference voltage of the generator G is set to 95 or higher due to the operating permissible conditions during operation.

That is, in steady operation, the generator terminal voltage is close to 100%, and the generator G is strongly excited and operates with a 1" delay and a power factor of 11.

If the field is lost here, the excitation of the generator G is lost and the power factor becomes 11, leading to a contact 57 of the reactive power relay.
The LD is closed, and the generator terminal voltage also becomes 90 times lower than the rated voltage, and the low voltage relay 27 operates to close the contact 27a.

As a result, the trip coil 52T of the parallel circuit breaker 52
is energized and the parallel circuit breaker 52 is tripped.

In this way, under the conditions that the automatic voltage regulator AVH is in use and the reference voltage setting device 90R is 95 or higher, even if there is a system disturbance due to a system fault, the voltage fluctuation conditions and reactive power substation conditions are completely maintained. Since the operation is opposite to the one shown in FIG.

In other words, if the voltage decreases, the automatic voltage regulator AV RJ will be more strongly excited, resulting in a 1' lag and a power factor of 1. If the voltage increases, the automatic voltage regulator AVRJ will be more weakly excited, leading by 1' and resulting in a power factor of 11, so this device Since this is the opposite of the detection condition, there is no possibility of erroneously detecting field loss.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an outline of an embodiment of a field loss detection device according to the present invention, and FIG. 2 is a control circuit diagram of the same embodiment. 57... Reactive power relay, 27... Low voltage relay,
AVR... automatic voltage regulator with reference voltage setter,
G...Synchronous generator, 90Rn...A set voltage detector that responds to the reference voltage set value of the AVR.

Claims (1)

[Claims] 1. An automatic voltage regulator for detecting field loss of a synchronous generator subjected to field control, which includes a set voltage detection device responsive to a reference voltage setting value of the automatic voltage regulator, and a set voltage detection device responsive to a reference voltage setting value of the automatic voltage regulator, and a set voltage detection device that responds to a reference voltage setting value of the automatic voltage regulator, and It is equipped with a reactive power relay that responds to the electric power f and a low voltage relay that responds to the terminal voltage of the generator, and when operating with the automatic voltage regulator, the set voltage detection device detects a certain standard necessary for steady operation. It detects that the power factor is set to more than the power value, it also detects that the reactive power relay has a leading power factor, and it also detects that the low voltage relay has a voltage drop that exceeds a certain value that is considered to be field loss. Field loss detection device that determines field loss based on the condition that the field loss occurs.