Current Protection Constraints Based Determination Method for Maximum Access Capacity of Inverter Interfaced DG

According to the fault characteristic of inverter interfaced DG (IIDG) controlled by low voltage ride through, the connection voltage and short-circuit current variation influenced by IIDG's capacity are analyzed when fault occurs in distribution system. It turns out that the connection voltage and current of IIDG vary nonlinearly as IIDG's output power increases continuously. According to these characteristics, a current protection constraints based determination method for maximum access capacity of IIDG is proposed, under the premise of ensuring traditional protection effectiveness. The simulation verified the effectiveness of the method.