Investigation on Fault Analysis for Power Transformers Using Adaptive Differential Relay

This article presents the fault analysis and differential protection scheme of the three phase Power Transformers (PT). The relay operates mainly during the internal fault condition and it must be insensitive to any fault outside the zone of protection. In this paper, a fuzzy logic based differential protection schemes has been used. It blocks the tripping through outer fault and internal fault conditions. The simulation result of FLC with disparity relay for 3 phase transformer shows fast tripping during internal fault and also avoids the mal operation of relay during external fault.