Relay protection method capable of quickly removing dead zone fault of transformer

Abstract

The invention relates to a relay protection method capable of quickly removing dead zone fault of a transformer. The relay protection method includes: during trip control of dead zone fault of one side of the transformer, setting conditions including a first condition and a second condition; if all the conditions are met, disconnecting a differential TA on the side of the transformer after delaying by a constant value, namely preventing current of the side of the transformer participating differential protection current calculation; if no conditions are met, then connecting the differential TA on the side of the transformer immediately, namely allowing current of the side of the transformer to involve in differential protection current calculation of the transformer. The first condition is that a spare strip protection outlet relay of the same of the transformer is in an acting stator or other electrical capacity protection (such as bus differential protection) strip outlet relay is in an acting state; the second condition is that the current of phase A, the current of phase B or the current of phase C of the side of the transformer reaches a setting value or zero-sequence current or negative-sequence current is larger than or equal to the setting value. The relay protection method has simple action principle, is high in reliability, and capable of removing dead zone faults of different sides and different voltage classes of the transformer quickly.

Description

technical field [0001] The invention belongs to the control technology of electric power transmission and distribution network, and relates to a relay protection method for quickly removing the fault in the dead zone of a transformer. Background technique [0002] GB / T 14285-2006 "Technical Regulations for Relay Protection and Safety Automatic Devices" stipulates that the transformer should be equipped with longitudinal differential protection as the main protection and the back-up protection for the transformer over-current caused by external phase-to-phase short circuit and ground short circuit. , where the backup protection for responding to phase-to-phase short circuit includes composite voltage overcurrent protection and phase-to-phase impedance protection, and the backup protection for responding to grounding short circuit includes zero-sequence current protection and grounding impedance protection. These backup protections are equipped with different backup protection...

AI Technical Summary

Problems solved by technology

Since the fault is outside the protection range of the transformer longitudinal differential protection, although the backup protection or other protection (such as busbar protection) on the fault side operates to trip the circuit breaker on the side of the transformer, the fault still exists. The protection action or the backup protection action of this side is used to trip the transformer general outlet relay circuit to trip the transformer power supply side circuit breaker to finally remove the fault. In this case, the time to remove the fault is generally longer; if the transformer is a high-impedance transformer, the backup protection on the transformer power supply side It may be that the short-circuit current does not reach the start-up value and the fault cannot be removed. Only when the transformer is burned to the point that the short-circuit current reaches and exceeds the protection start-up value can the backup protection on the power supply side of the transformer be activated to remove the fault.

Although the invention patent ZL200810201305.3 "Relay Protection Method for Eliminating Transformer Dead-zone Faults" proposes a scheme to trip the circuit breakers on the other side of the transformer after judging the dead-zone fault, the time to remove the fault is still a little long, and it is only suitable for 110kV transformers

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