Local Area Conventional Protection

Higher demand is putting stress on the reliability, rapidity and sensitivity of local area conventional protection. This chapter introduces an improved scheme for transformer differential protection and new protection schemes different from differential protection. In the chapter, voltage and current information are comprehensively utilized and a few new transformer protection schemes are constructed based on equivalent instantaneous leakage inductance and generalized instantaneous power. These schemes can efficiently solve the problems of lack of sensitivity when no‐load switching at faults and malfunction in the case of TA saturation due to external fault. With regard to transformer protection, the demand for high reliability and rapid response are on the increase, with larger capacity transformers constantly being brought into operation. The chapter further introduces a new location method for multiple inter‐line and grounded faults of double‐circuit transmission lines based on compensation voltage.