Abstract:Error test is an important means to ensure accuracy of power transformer. When the error test is carried out at the equipment operation site, it is not only faced with the impact of the surrounding equipment, but also needs to complete the complex test wiring and eliminate the interference of the non-test loop, so when the test results are abnormal, it will be very difficult to troubleshoot the problem. In view of this problem, this paper discusses six typical field test faults of power transformer error test combined with actual field cases, analyzes the fault characteristics, fault causes, occurrence locations and other dimensions, and summarizes the ideas and suggestions for troubleshooting by extracting the characteristics of typical faults and combining the detection information given by the calibrator. At the same time, the prominent safety risk points in the test process are analyzed, and the operation risk investigation suggestions are put forward, which effectively reduces the operation risk and ensures the safety of personnel and equipment