Adaptive Reclosing Scheme for flexible Multi-Terminal DC Distribution Grid

For flexible medium-voltage DC distribution grid based on overhead line, this paper proposes an adaptive reclosing scheme. First, the characteristic differences of capacitive coupling voltage between the instantaneous fault and the permanent fault are analyzed. Afterwards a fault property identification criterion is constructed based on capacitive coupling voltage. Through comparing capacitive coupling voltage on disconnected pole, the scheme can identify the instantaneous fault from the permanent one. A modular multilevel converter (MMC)-based multi-terminal DC distribution grid is constructed using PSCAD/EMTDC, and extensive simulations are conducted to validate the effectiveness of proposed scheme. Simulation results show that the proposed adaptive reclosing strategy can detect fault property accurately.