CN206076925U - Secondary circuit of transformer protection interlocking cutting generator matched line - Google Patents

Abstract

The utility model provides a secondary circuit for transformer protection interlocking and cutting generator distribution outlets. Two closing switches KK and circuit breaker auxiliary contacts are sequentially connected in series between the control bus input terminal +KM and the control bus output terminal -KM. QF and switch trip coil TQ. In the utility model, a transformer primary isolating switch normally open auxiliary contact QS is connected before the pressure plate LP of the generator distribution outlet of the transformer, and the other end of the transformer primary isolating switch normally open auxiliary contact QS is connected with the transformer protection action contact JD. When the transformer is being tested for protection, the primary isolating switch must be disconnected, and QS is also disconnected. At this time, even if the pressure plate LP of the outgoing line of the motor is continuously developed, because QS is disconnected, the circuit loses the positive power supply, and the generator will not be able to distribute the outgoing line. Switch off, so as to avoid non-accident trip shutdown, reduce economic losses, and ensure safe power supply.

Description

Transformer protection interlock cuts the secondary circuit of generator distribution line

technical field

The utility model belongs to the field of electric circuits, in particular to a transformer protection interlock for preventing a transformer protection test from accidentally disconnecting a generator and cutting a secondary circuit of a generator distribution line.

Background technique

As people's awareness of energy conservation and environmental protection increases, more and more energy-saving and environmentally friendly generators are newly added, especially in steel systems, many blast furnace residual pressure generators and gas-fired TRT generators are newly installed, and most generators are It is connected to the lower-level substation brought by the outgoing line of the general step-down substation, the voltage level is 10kV or 6kV, and the grid connection point is at the entrance of the lower-level substation.

In order to prevent the occurrence of asynchronous closing accidents when the generator is connected to the grid, an interlock is installed between the secondary switch of the main transformer and the switch of the generator sending line. Transformer overcurrent, differential, and heavy gas protection action, tripping and switching off the primary and secondary switches of the main transformer, and simultaneously switching off the switch of the generator distribution line. On the protective screen of the transformer, there is a pressure plate for cutting the generator distribution line, and whether to cut the generator distribution line is controlled by the pressure plate. However, the defect exists: sometimes the test personnel or the personnel on duty in the substation forget to disconnect the pressure plate during the transformer test, which will cause the generator distribution line in normal operation to trip, cause artificial accidents to stop, and bring a lot of problems. economic loss.

Contents of the invention

The utility model provides a secondary circuit for transformer protection interlocking and cutting generator distribution lines, the purpose of which is to prevent the tripping of generator distribution lines that have an interlocking relationship with the transformer due to miscutting during the transformer protection test, so as to avoid non-accident shutdown .

For this reason, the technical solution that the utility model takes is:

A secondary circuit for transformer protection interlocking and generator distribution outlets, in which two closing switches KK, circuit breaker auxiliary contacts QF and switches are sequentially connected in series between the control bus input terminal +KM and the control bus output terminal -KM The tripping coil TQ, the transformer protection action contact JD of the transformer cut-off generator distribution line is connected to the control bus input terminal +KM at one end, and the other end is connected in series with the pressure plate LP, and the other end of the pressure plate LP is connected in front of the auxiliary contact QF of the circuit breaker. In the utility model, a transformer primary isolation switch normally open auxiliary contact QS is connected in front of the pressure plate LP, and the other end of the transformer primary isolation switch normally open auxiliary contact QS is connected with the transformer protection action contact JD.

The beneficial effects of the utility model are:

When the transformer is being tested for protection, the primary isolating switch must be disconnected, and QS is also disconnected. At this time, even if the pressure plate LP of the motor sending out line is continuously developed, because QS is disconnected, this circuit loses the positive power supply, and the generator will not be able to distribute the wire. Switch off, so as to avoid non-accident trip shutdown, reduce economic losses, and ensure safe power supply.

Description of drawings

Figure 1 is the secondary circuit diagram of the original transformer protection interlock cut generator distribution line;

Figure 2 is the secondary circuit diagram of the modified transformer protection interlock cut generator distribution line.

In the figure: control bus input terminal +KM, control bus output terminal -KM, closing switch KK, circuit breaker auxiliary contact QF, switch trip coil TQ, transformer protection action contact JD, pressure plate LP, transformer primary isolating switch normally open auxiliary Contact QS.

detailed description

It can be seen from Figure 1 that the original transformer protection interlock cuts the secondary circuit of the generator distribution line, and there are two closing switches KK and circuit breaker auxiliary contacts in series between the control bus input terminal +KM and the control bus output terminal -KM QF and the trip coil TQ of the switch, one end of the transformer protection action contact JD of the transformer cut-off generator distribution line is connected to the control bus input terminal +KM, the other end is connected in series with the pressure plate LP, and the other end of the pressure plate LP is connected in front of the auxiliary contact QF of the circuit breaker.

Figure 2 shows that the utility model connects a transformer primary isolating switch normally open auxiliary contact QS before the pressure plate LP, and the other end of the transformer primary isolating switch normally open auxiliary contact QS is connected with the transformer protection action contact JD. Thus avoiding the tripping of the generator distribution line caused by mistakenly disconnecting the generator during the transformer protection test.

Claims (1)

1. A secondary circuit for transformer protection interlocking and generator distribution outlets. Two closing switches KK, circuit breaker auxiliary contacts QF and One end of the tripping coil TQ of the switch, the transformer protection action contact JD of the transformer cut-off generator distribution line is connected to the control bus input terminal +KM, the other end is connected in series with the pressure plate LP, and the other end of the pressure plate LP is connected in front of the auxiliary contact QF of the circuit breaker. It is characterized in that, A transformer primary isolating switch normally open auxiliary contact QS is connected in front of the pressure plate LP, and the other end of the transformer primary isolating switch normally open auxiliary contact QS is connected to the transformer protection action contact JD.