A fault ride through strategy of multi-ports DC transformer

DC transformer (DCT) is the main and key equipment of DC distribution network. Multi-ports DCT can connect multiple DC lines or networks at the same time, which has high power supply reliability and is suitable for interconnection equipment among different DC power grids. As an important node in DC distribution network, multi-ports DCT not only operates under normal conditions, but also needs to deal with the impact of DC system fault, among which short circuit fault is the most common one. In this paper, the short-circuit characteristics of multi-ports DCT operating in three different modes are analyzed. The analysis shows that when a single port of the multi-ports DCT fails, the fault ride through of the multi-ports DCT cannot be realized only by changing the operation mode to block the port. This paper investigates a fault ride through strategy based on solid state circuit breaker and feedforward decoupling control method. The simulation results verify the fault characteristics of the multi-ports DCT under different operating modes, and verify the effectiveness of the proposed fault ride through strategy.