| Popis: |
The temporary fault probability of overhead (OH) lines is greatly higher than cables. For multi-terminal DC (MTDC) grids, the power supply of OH lines can be restored immediately by reclosing the hybrid DC circuit breaker (HCB) after the temporary fault occurs, consequently greatly shortening power outages. In order to solve problems of protection maloperation, power electronics damage, etc. may be caused by the non-selective reclosing of HCB, the line fault identification principle (LFIP) based on active small traveling wave signal injection was proposed in this paper. The small traveling wave signal can be injected into the DC line by unblocking some sub-modules (SMs) in the transfer branch of HCB. Then whether the fault exists on the line can be determined by the difference in propagation characteristics of the injected signal. Simulation results confirm the effective performance of the proposed method. |
