Optimum Coordination of Overcurrent Relays with Active Superconducting Current Controller in Distribution Systems

The Active Superconducting Current Controller (ASCC) is a new type of Fault Current Limiters which can limit the fault current in different modes and also has the particular abilities of compensating active and reactive power for AC main circuit in the normal state. The use of the ASCC disturbs the operation of Over Current Relays (OCR) used in the distribution system. In this paper, an optimum method is proposed for protective coordination of OCR when the ASCC is applied in the system and operates in different modes. By adjusting the magnitude and phase angle of compensation current and also by adjusting the setting parameters of OCR such as Time Dial and Pick up Current in the optimum values, the protective coordination is obtained. By using MATLAB, the model of the distribution system with the ASCC is built and the impact of this type of FCL on the over current relays protection is studied in detail under different current-limiting modes.