SU1179472A1 - Device for protection of autotransformer against incomplete phase operation - Google Patents

Abstract

DEVICE FOR TRANSFER FROM AUTOMATIC TRANSFER FROM FULL-PHASE OPERATION MODE, including zero-sequence current transformers installed on the sides of the highest and medium voltage of the autotransformer, the secondary windings of current transformers are connected to current relays, the first and second directional action organs, the first inputs of which are intended for connection to transformers installed on the sides of the high and medium voltage autotransformer, the first time relay, the coil Secondly, it is connected to the supply circuit by operating current through the closing contacts of current relays connected in parallel with each other and in series with parallel connected first closing contacts of directional action organs, characterized in that, in order to increase the selectivity, a second time relay and diode are added, the second inputs directional organs are designed to be connected to a voltage transformer installed on the lower voltage side of the autotransformer, winding The time relay is connected in parallel to the winding of the first time relay, the contact contacts of the first time relay are connected in series and the diode is connected I in parallel with the first contact of the directional actuators, (L is connected to the common connection point of the diode and the closing contact of the first time relay the second closing contact of the first directional organ and the first closing contact of the second time relay, intended to be connected to the circuit The switch on the side of the higher voltage of the autotransformer hdra, as well as connected in parallel to each other a second closing contact of the second directional action organ and a second closing contact of the second time relay, designed to connect to the circuit breaker disconnecting switch on the side of the middle voltage of the motor.

Description

The invention relates to electrical engineering, as well as to the relay protection of elements of energy systems, and can be used to protect transformers and autotransformers from incomplete phase operation modes. The purpose of the invention is to demonstrate the selective nature of the action of protection. FIG. 1 shows a device diagram; in fig. 2 is one of the embodiments of the directional action organ. A device for protecting an autotransformer from an incomplete phase mode is installed (FIG. 1) on an autotransformer 1 connected to the network via switches 2,3 and 4. Voltage transformers 5,6 and 7 are installed on the sides of the higher, middle and lower voltages of the autotransformer, respectively On the sides of the middle and higher voltages, zero-sequence current transformers 8 and 9 are installed, to the secondary windings of which current relays 10 and 11 are connected. Directional action body 12 is connected to voltage transformers 6 and 7, and the directional organ 13 to the voltage transformers 5 and 7. The operational circuits of the circuit contain the closure of the contacts 14 and 15 of the organ of the directional action 12, the closing contacts 16 and 17 of the organ of the directional action 13, the short circuit of the contacts 18 and 19 of the current relay 10 and 11, the winding of the first time relay 20 with the closing contact 2 1, the winding of the second time relay 22 with the closing contacts 23, 24 and the diode 25. Directional action bodies 12 and 13 can be filled in the form of an org containing (Fig. 2) negative sequence voltage filters 26 rectangular pulse shapers 27, a phase-sensitive unit 28, a threshold element 29 and an output unit 30, Directional Action Bodies 12 and 13 compare the phase of the negative-sequence voltage on the sides of the middle and highest voltages with voltage Reverse sequence on the low voltage side. Contacts 14-17 of organs 12 and 13 are closed if the voltages supplied to the organs do not coincide in phase. In the presence of internal longitudinal asymmetry, the voltages applied to the directional organs are in antiphase, at least for one organ. With external longitudinal or transverse asymmetry, the voltages applied to the relay are in phase, and in this mode the directional organs do not operate. The security device operates as follows. When internal longitudinal asymmetry is caused by the failure to turn on one or two phases of the switch, for example, on the higher voltage side, directional action body 13 is activated and closes its contacts 16 and 17, since the voltages applied to this body are in antiphase and As a result of asymmetry, current organ 10 or 11 (contacts 18 or 19 are closed). This causes the start of the first and second time relay. Through the time delay, tuned from the time of the phase-switching time of the switch, contact 21 of the first time relay closes and a trip circuit appears through the closed contacts 17 and 21. Thus, the autotransformer disconnects only from the asymmetry that has occurred. At the same time, the power supply of the load on the lower voltage side is maintained. If the asymmetrical mode is not eliminated in this way, it modifies the second time relay 22 and. with its contacts 23 and 24, it provides for the disconnection of the autodischarge generator from all sides. The shunting of contacts 14 and 16 by contact 21 of the first time relay 20 improves the reliability of operation of circuit1 1. If external longitudinal or transverse asymmetry is present, only current relay 10 and 11 can be triggered, since their settings to pick up the sensitivity of the device should be chosen as M (wno less, and The bodies on the days of PRAUTION do not work.

Claims (1)

DEVICE FOR PROTECTING THE AUTOMATIC TRANSFORMER AGAINST THE PERFORMANCE OPERATION MODE, including zero-sequence current transformers installed on the sides of the highest and average voltages of the autotransformer, the secondary windings of current transformers are connected to current relays, the first and second directional organs, the first inputs of which are intended for connection to transformers voltage installed respectively on the sides of the higher and medium voltage autotransformer, the first time relay, the winding of which it is connected to the power supply circuit with operating current through the closing contacts of current relays connected in parallel with each other and in series with parallel connected first closing contacts of directional organs, characterized in that, in order to increase selectivity, a second time relay and a diode are additionally introduced, and the second inputs of the organs directional actions are designed to connect to a voltage transformer installed on the low voltage side of the autotransformer, the windings of the second time relay parallel to the winding of the first time relay, connected in series to the first contacts of the first time relay and the diode are connected in parallel to the first make contacts of the directional organs, while the second make contact of the first connected in parallel to the common point of the diode and the make contact of the first time relay body of the directed action and the first closing contact of the second time relay, designed to connect to the circuit breaker circuit breaker on the high side its voltage autotransformer, and also connected in parallel are connected between a second normally open contact of the second body and the second directional eamykayuschy second contact time relays for connection to the circuit breaker tripping on the medium voltage of the autotransformer.