Improved Longitudinal Protection for T-connected Inverter Interfaced Distributed Generation Distribution Network

Inverter interfaced distributed generator (IIDG) is connected to the distribution network in the form of T-connected, which changes the operating characteristics of single power flow direction in the traditional distribution network, and makes the traditional three-stage current protection no longer applicable. Therefore, this paper proposes an improved longitudinal protection method for T-connected inverter distributed power distribution networks. The control strategy of IIDG is analyzed, and the analysis method in a distribution network is given. On this basis, an improved criterion of longitudinal protection is proposed. The proposed criterion can sensitively identify internal and external faults that is not affected by DGs. Simulation results of PSCAD verify the effectiveness of the proposed method.