Polarity test method for differential protection current transformers of autotransformers based on short circuit current rising test of hydro generators
Abstract：Polarity verification of current transformers is a key step to ensure the normal operation of differential protection for newly commissioned or modified transformers. Considering the limitations of traditional methods, including incomplete circuit verification, high equipment costs, complex testing procedures, and higher safety risks, this paper proposes a new polarity verification method suitable for hydropower stations. This method makes full use of existing equipment of the hydropower station, conducting short circuit current-rising tests through the turbine generator and transformer to generate through currents in order to verify the correctness of the polarity of current transformers on each side of the busbar differential protection. This paper details the implementation plan of this method, analyzes and calculates the key aspects of the testing process, and establishes comprehensive safety control measures. Comparison of test data with theoretical calculations shows that this method can effectively and reliably verify the polarity of current circuits. Compared with traditional methods, this method has significant advantages such as higher safety, lower cost, no need for additional testing equipment, and wider applicability, providing reference for the polarity verification of current transformers in hydropower and pumped-storage power stations.
汪平, 杨令, 邓文涛, 孙知键. 基于水电机组短路升流试验的自耦变压器差动保护电流互感器极性检验方法[J]. 电气技术, 2026, 27(5): 71-79.
WANG Ping, YANG Ling, DENG Wentao, SUN Zhijian. Polarity test method for differential protection current transformers of autotransformers based on short circuit current rising test of hydro generators. Electrical Engineering, 2026, 27(5): 71-79.
2026, Vol. 27 
