Transformer dead-zone fault relay protection method based on short-time open protection and sealed TAs

Abstract

The invention relates to a transformer dead-zone fault relay protection method based on short-time open protection and sealed TAs. According to the method, in trip control of certain-side dead-zone faults of a transformer, three conditions are set, wherein as for the first condition, a certain-side backup protection trip outlet relay of the transformer is in an action state, and alternatively other electrical quality trip outlet relays are in action states; as for the second condition, when the first condition is met, pulse T time open protection is started one time; as for the third condition, a certain-side A-phase or B-phase or C-phase current Ipmax of the transformer reaches a starting value, and alternatively a zero-sequence current Io or a negative-sequence current I2 reaches the starting value and namely is greater than or equal to a set value; when the conditions are met, the certain-side transformer differential protection TA of the transformer is quitted after time delay; when any one condition is not met and alternatively after open protection time T arrives, the certain-side transformer differential TA of the transformer is accessed by 0s. According to the transformer dead-zone fault relay protection method, action principles are simple, reliability is high, and various voltage class dead-zone faults on all sides of the transformer can be removed rapidly.

Description

technical field [0001] The invention belongs to the control technology of electric power transmission and distribution network, and relates to a transformer dead zone fault relay protection method based on short-time open protection and sealing TA. 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 bac...

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 general outlet circuit of the transformer and trip the circuit breaker on the power side of the transformer to finally remove the fault. In this case, the time to remove the fault is generally longer; Since the short-circuit current does not reach the start-up fixed value, the fault cannot be removed. Only when the transformer is burned to the point where the short-circuit current reaches and exceeds the start-up value of the backup protection can the backup protection on the power supply side of the transformer be activated to remove the fault.

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