Method for checking differential protection secondary circuit of transformer

Abstract

The invention discloses a method for checking a differential protection secondary circuit of a transformer, and belongs to the field of differential protection of an electric power system. Through a mode of arranging a three-phase large current generator on the low voltage side of the transformer, the checking method solves the problem that an on-load test of secondary connection of a differential protection current transformer of the transformer cannot be carried out because the load current of the conventional to-be-protected transformer is too low. The checking method judges whether the parameter setting of a differential protection device is correct by means of comparing the induced current, acquired by the differential protection device, of a secondary winding of the current transformer with the theoretical value. The checking method judges whether the connection of a differential protection secondary circuit is right according to the condition that whether the differential current is 0. The checking method judges whether the polarity of the current transformer of the differential protection secondary circuit is correct according to the condition that whether the induced current of the secondary winding of the same-side three-phase current transformer is in a positive phase sequence. The method is suitable for checking the differential protection secondary circuit of the transformer.

Description

technical field [0001] The invention relates to a checking method for a secondary circuit of differential protection, which belongs to the field of differential protection of electric power systems. Background technique [0002] Transformer differential protection, as the main protection of transformers, has a very high sensitivity to faults in the protection zone. However, often due to the incorrect secondary wiring of the current transformer, the correct action rate of the transformer differential protection is low. In actual work, in order to judge whether the secondary wiring of the transformer differential protection current transformer is correct, it is necessary not only to analyze it theoretically, but also to conduct a load test on it. [0003] The current on-load test method for the secondary wiring of the existing transformer differential protection current transformer is: adjust the primary operation mode of the system so that the equipment in operation is conne...

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Problems solved by technology

[0004] In order to solve the problem that the load test of the secondary connection of the transformer differential protection current transformer cannot be carried out due to the too small load current of the transformer to be protected, the present invention proposes a checking method for the secondary circuit of the transformer differential protection

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