Research on Short-Circuit Test and Simulation of CSG First Mechanical HVDC Circuit Breaker in VSC-HVDC

Artificial instantaneous grounding test of DC overhead lines is a key step to verify the high-speed DC circuit breakers' rapid breaking performance and the control and protection strategies of VSC-HVDC. This paper introduced the artificial grounding test method of first mechanical HVDC circuit breaker in CSG, PSCAD software was used to simulate the key parameters such as breaking current and LC oscillation current of DC circuit breaker. The field tests and simulation comparison show that arc extinguishing of mechanical fracture delays 3.5ms after receiving the DC protection action, and the cut-off current is 1370A, the arrester in DC circuit breaker did not act, and the LC oscillating current is fed into DC line. Subsequent applications should pay attention to the influence of the LC oscillating current of the mechanical HVDC breaker on the protection of VSC-HVDC.