In view of the tripping accident of the auto-transformer three side caused by the bushing fault on the medium voltage side of an auto-transformer in a 500 kV substation,the correctness of each protection action related to this accident is evaluated in combination with the protection tripping report and fault recording files.Compare with the phase of each TA current,it calculates the differential current and braking current,analyzes and determine that the fault point is located in the bushing at the medium voltage side and the development process of the bushing fault point,and the reasons for the non action of the side differential protection are analyzed and described in detail.It provides relevant technicians with the analysis experience of the protection action of the near fault at the medium voltage side of the auto-transformer,and improves the power grid operation management level.
维普
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