A Current-Based Solution for Transformer Differential Protection Part II: Relay Description and Evaluation

This paper describes a new approach for transformer differential protection that ensures security for extemal faults, inrush, and overexcitation conditions and provides dependability for internal faults. This approach combines harmonic restraint and blocking methods with a wave shape recognition technique. We compare in the paper the behavior of some traditional transformer protection methods to that of the new method for real cases of magnetizing inrush conditions.