Analysis of Stage Difference Coordination of Protective Devices in Direct Current System

Abstract

Stage difference coordination is an important part of DC system. Taking the GM series two-stage DC circuit breaker and the GMB series three-stage DC circuit breaker as examples, the protection characteristics of the DC circuit breaker are described. The 220kV substation is taken as an example to analyze the DC connection mode and protection analysis of the control loop and closing circuit. The analysis proves that the level difference plays an important role in the stability of the DC system. This paper provides a reliable basis for perfecting the stage difference coordination of the power system in DC systems.