A novel real-time estimation method for fault current of inverter-interfaced distributed generations T connecting in feeder

The acquisition for fault currents of gridconnected distributed generations is of great significance to improve the performance of protection in distribution network. Therefore, this paper proposes a novel real-time estimation method for fault currents of distributed generations. Considering the low voltage ride through (LVRT) control strategy, the fault equivalent model of inverter-interfaced distributed generation (IIDG) is established firstly. Besides, a method for calculating the positive-sequence voltage at the point of common coupling (PCC) is put forward. Then, based on the electric information including current and voltage at both sides of the feeder, a real time estimation method for fault current of IIDGs is proposed. The accuracy of the proposed method is verified by a 10kV distribution network with multi-IIDGs established in PSCAD/EMTDC at last.