Method to identify faults of electric operating device; uses active power, distorting and displacement wattless powers, unsymmetrical actual and differential powers

摘要

The method involves computing an active power, a distorting wattless power, displacement wattless powers, asymmetrical effective powers and their differential powers from determined and digitalized input and output side conductor currents and conductor-earth voltages. These computer powers are each compared with operating parameters. A fault or type of fault can be detected and located from the comparison results. An Independent claim is included for a device for implementing the method.