Diagnosis of interturn faults of voltage transformer using excitation current and phase difference

Abstract

The interturn faults of voltage transformers will cause inaccurate data collection, wrong decision and wrong action of relay protection in power system. It is necessary to put forward an effective on method about the voltage transformer assessment. Two novel sensitive methods based on the excitation current and the phase difference between primary voltage and the excitation current (phase difference) for identifying interturn faults during energization of voltage transformer are presented. The kirchhoff’s voltage equation (KVE) are provided by calculating the excitation current and phase difference between primary voltage and excitation current (phase difference). The proposed method was analyzed during the simulations and experimental tests were also carried out in laboratory to validate the results. The results indicate that the severity of interturn fault is positively correlated with the excitation current, and negatively correlated with the phase difference. Furthermore, the phase difference can effectively detect early interturn fault of voltage transformer.