A New Criterion for Main Protection of Traction Transformers

摘要

It is difficult for traditional protection to differentiate inrush currents from internal fault currents of traction transformers.To solve this problem,the paper proposes a new criterion based on dead angle of the differential currents.The criterion uses wavelet transform to process inrush currents and internal fault currents of traction transformers and obtains obvious different characteristics of their dead angles.These characteristics can be efficiently used to discriminate between inrush currents and internal fault currents of traction transformers.Simulation results verify the feasibility and effectiveness of the criterion.