| Abstract |
This study develops a rapid protection method for flexible DC grids. Based on the principle of modulus decomposition, common-mode (CM) and differential-mode (DM) circuits of MMC, DC transmission line, and fault transition resistance under different faults are derived, and the synthesized equivalent circuit of DC grids are finally obtained. The method utilizes a single-end derivative of CM and DM currents to construct a protection phase plane that divides different DC fault types into different regions. The proposed method is verified by simulation and experiment. This method can identify and detect faults within 1ms, which can significantly reduce the breaking current of the DC circuit breaker (DCCB). |
