A Low-Breaking-Fnergy-Needed Fault Isolation Scheme Based on Fault Active Control for DC Distribution Network with Multi-type Converters

The direct current (DC) distribution network is promising with the development of renewable energies and the hybrid application of multi-type converters is optimal in reducing the construction cost. Under such conditions, converters with fault control capability can be utilized to reduce the breaking capacity of DC circuit breakers (DCCBs), which can further save the cost of isolation devices. Therefore, this paper proposes the current absorbing control to reduce the faulty line's current and thus lower the DCCB's breaking capacity. Then the breaking capacity of DCCB based on the proposed fault control in different network topologies is analyzed. Features of the DCCB's breaking capacity are concluded, and a coefficient is introduced to provide a reference for DCCB selection. Finally, the tested system is built in PSCAD/EMTDC, and simulations verify that the proposed scheme could reduce the faulty line's current and lower the breaking capacity effectively.