Development of an HVDC Circuit-Breaker and the Study of Testing Methods

HVDC circuit-breakers (DC-CBs) are used in a multi-terminal high-voltage DC (MT-HVDC) transmission systems to isolate faulted sections from healthy ones. The development of a 550 kV voltage source converter assisted resonant current (VARC) DC circuit-breaker (DCCB) is in progress. A DC-CB typically consists of a current suppression device (CSD) that can suppress the fault current to zero and a residual current switch (RCS) that can interrupt the residual current. The VARC CSD consists of multiple units connected in series, with each unit generating a TIV of approximately 50 kV. By changing the number of units connected in series, the rated voltage and the maximum amount of energy can be changed.