Multi-Feeder Protection System with Hybrid Circuit Breakers for MVDC Grids

摘要

Medium voltage direct current (MVDC) grids are proposed as a solution for future distribution systems providing advantages of lower transmission losses and high controllability. Protection of a DC grid is more challenging than AC systems due to fast fault propagation and high peak currents as well as lack of current zero crossing. Until now, proposed hybrid DC circuit breakers have been based on the power electronic components and considerably more expensive than AC circuit breakers. In case when DC circuit breakers are applied at each individual feeder, the cost of the MVDC grid increases significantly. In this paper, a multi-feeder protection system is proposed that utilizes the main power electronic part of the circuit breaker for several feeders' protection. The proposed solution allows the reduction of the protection system costs maintaining fast fault clearing capability provided by hybrid DC circuit breakers. Design evaluation of the protection system components is described in detail. Proposed multi-feeder protection solution is potentially capable to be used with any hybrid circuit breaker topology.