Speakers
Description
To efficiently protect a high voltage direct current (HVDC) system containing line commutated converter (LCC) and voltage source converter (VSC), this study proposes to coordinate resistive superconducting fault current limiters (SFCLs) and hybrid DC circuit breakers (HDCBs) to clear the DC line fault. The principle modeling of the resistive SFCLs is stated, and the impacts of the SFCLs on the DC fault currents of the LCC and VSC stations are analyzed. In terms of that the DC fault current interruption involves multi-stages, the coordination time sequence between the SFCL and the HDCB in the LCC/VSC station is given. Using PSCAD/EMTDC, a 320 kV class HVDC system is created. The change of the SFCL size and the HDCB operation delay is simulated, and the performance indexes including the DC fault current level, breaking time and dissipated energy are compared. It is confirmed that the proposed approach is effective in handling the fault. Especially for the VSC station, the approach is to visibly reduce the DC fault current and shorten the transient voltage duration on the HDCB, and the dissipated energy of the HDCB is dramatically reduced. For the LCC station, the approach may act as a competitive backup to ensure a timely current breaking. As a result, the DC fault can be removed more rapidly and reliably.
