Current increment based DC differential protection method

Large scale application of renewable energy in distribution network generates more challenges for traditional protection methods. Longitudinal differential protection is a common backup protection method of DC system. It adopts measurements at the both ends of the line, and has a good performance in most cases except faults with high grounding resistance. To improve the protection reliability of DC distribution networks, this paper proposes a current increment direction based differential protection method. First, the current characteristics of various DC faults are analyzed. Then, the protection method is descripted. Finally, a DC distribution network is modeled on the platform of MATLAB/Simulink to test the performance of proposed method. Simulation results show the proposed method can operate accurately and be immune to large variations of grounding resistances and disturbances.