Analysis of Differential Protection Principle and Key Technology of Through-Current Test of UHV Transformer

The main transformer of UHV substation adopts neutral point non-excitation voltage regulation, and its differential protection winding wiring principle and key technical nodes of through-current test have significant research value. According to the structural principle of the main transformer and voltage regulator compensation transformer, and combined with the analysis of the polarity of the current transformer in the process of voltage regulation of the UHV transformer, this paper aims to ensure that the differential protection can act accurately and correctly under various internal faults and external abnormal conditions. In addition, this paper also describes in detail the key technical nodes in the process of UHV transformer secondary circuit current test, in order to meet the needs of field current, so as to ensure that the actual working condition of the transformer is effectively reflected. These research results will provide a favorable basis and method for UHV substation transformers in actual engineering applications and equipment maintenance.