Relay Protection Method and Device for Quickly Cutting off Empty Charging in Transformer Dead Zone Fault

Abstract

The invention discloses a relay protection method and device for quickly cutting off the fault of empty charging in the dead zone of a transformer, including the following control process: the circuit breakers on each side of the transformer are in the opening position, and the current on one side changes from no flow to flow and When the circuit breaker on this side is turned from the minute position to the close position, the transformer is in the state of empty charging from this side; the transformer is empty charging, and the dead zone protection is opened for T seconds; the circuit breaker on a non-empty charging side of the transformer is in the opening position; The maximum phase current of the three-phase current on the charging side is greater than the current setting value, or the zero-sequence current is greater than the zero-sequence setting value, or the negative-sequence current is greater than the negative-sequence setting value; when the above conditions are met, the transformer differential protection will be activated after a delay of t1 The tripping action exits the circuit, trips the circuit breakers on each side of the transformer, and quickly removes the fault in the dead zone. The invention avoids the influence of inrush current when the transformer is empty-charging, has nothing to do with the setting value of the backup protection of the transformer, the type of the transformer and the type of the fault, and greatly shortens the removal time of the fault in the dead zone.

Description

technical field [0001] The invention relates to the technical field of relay protection of power systems, in particular to a relay protection method and device for quickly removing a transformer empty-charging dead zone fault. Background technique [0002] Transformer dead zone fault refers to the short-circuit fault that occurs between the circuit breaker on one side of the transformer and the current transformer on the side used for differential protection of the transformer (see figure 2 ), the dead zone fault is the fault at the outlet of the transformer, the fault current is large, and the impact on the transformer is large. The fault is outside the differential protection range of the transformer. Even if the backup protection or bus differential protection on this side trips the circuit breaker on this side, the The fault cannot be isolated. Only when the backup protection action on the power supply side or the backup protection action on the side trips the circuit br...

AI Technical Summary

Problems solved by technology

[0012] Invention patents 201310641842.0 and 201410039071.2 propose a method for removing transformer dead-zone faults. When a dead-zone fault occurs on one side of the transformer, TA on that side exits the differential protection, making the transformer differential protection trip the circuit breakers on each side. The faults in the dead zones on each side also have the disadvantages of the methods proposed in the invention patents 201310641634.0 and 201310641655.2, and due to the influence of the transformer inrush current during empty charging, the differential protection may not operate or delay the operation.

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