Abstract:

Taking a stator grounding fault protection caused by interturn short circuit of voltage transformer as an example, the interturn short circuit of voltage transformer primary winding is determined to be the cause of the protection action through comprehensive analysis of fault waveform and test data. The analysis and calculation on equivalent circuit of terminal voltage imbalance caused by the equivalent impedance reduction as the voltage transformer interturn circuit is shorted are made, which is helpful to understand the process of interturn short circuit. Finally, several possible situations and preventive measures leading to interturn short circuit are discussed, which can provide reference for the monitoring and safe operation of voltage transformer.

Key words:

voltage transformer, interturn short circuit, equivalent circuit, preventive measure