Study on fault current characteristics and fault analysis method of power grid with inverter interfaced distributed generation

In order to meet the grid code of distributed generation, a control strategy for low voltage ride through (LVRT) of inverter interfaced distributed generation (IIDG) is proposed. Based on it, the dynamic responses of inverter controller and fault current characteristics of IIDG are studied under conditions of symmetric fault and asymmetric fault. Besides, the calculation model of the fault current of IIDG is established. Moreover, the fault analysis method for the distribution network with penetration of IIDGs is analyzed. Digital simulation results validate the correctness of the theoretical analysis results. The research results are helpful to improve the LVRT capability of IIDG and study the fault characteristics of the power grid with IIDGs. The research results can also provide reference for principle study and performance evaluation of the relaying protection which is applicable for the power gird with penetration of IIDGs. © 2013 Chin. Soc. for Elec. Eng.