A Fault Location Method for DC Micro-Grid Based on the Improved Analytical Method

In order to realize large-scale DC micro-grid, the effectively fault location method is the key technology to ensure the safe operation of flexible DC grid. Aiming at the common fault analysis method considers the current on the fault line is due to the adjacent converter station for fault location.The paper proposed a improved fault analysis method based on adjacent circuits of fault points, which considers that the multiband current on the fault line is the sum of the current components flowing into the fault point at various converter stations. After simplifying the fault equation by using the intrinsic characteristics of fault transient variables at the initial moment, it is found that the fault location is only related to the current change rate on the fault line. Finally, a six-terminal ring model was built in SIMULINK platform to simulate the proposed method, the result shows that the proposed method can quickly identify faults and reliably locate them, and can meet the fault location requirements of DC microgrid.