Impact of fault current limiter on VSC-HVDC DC protection

Multi-terminal Voltage-Sourced Converter (VSC) High Voltage Direct Current (HVDC) transmission is expected to play a key role in future power transmission grids. Compared with AC transmission, DC transmission is more vulnerable to faults due to the lower DC side impedances and sensitive power electronics used in the converters. DC protection issues must be solved before any multi-terminal VSC-HVDC grid can be established. In terms of DC protection, apart from using a DC circuit breaker to interrupt and isolate a DC fault, a Fault Current Limiter (FCL) may be employed to limit the fault current. FCLs could potentially form an important part of any future DC protection system. This paper investigates such a FCL. The main contribution of this paper is that, the resistive type superconducting FCL (SCFCL) is modelled in detail to perform DC protection with the ABB hybrid circuit breaker, in a high fidelity four-terminal VSC-HVDC system model. The simulation results show that the SCFCL has great potential to be employed for DC protection.