Whole‐line fault analysis method for unbalanced distribution networks with inverter interfaced distributed generators

Abstract

The integration of the inverter interfaced distributed generators (IIDGs) challenges the conventional fault analysis in distribution networks. However, the existing analysis methods mainly focus on the fault occurring at the network buses and little research has been done to analyse the whole-line faults. To extend the fault analysis methods, this paper proposed a phase domain estimation method. The new method was designed to analyse the whole-line faults in unbalanced distribution networks, considering the control strategy and fault-ride-through (FRT) capability of IIDG. A canonical method was developed and a compensation method was utilised, avoiding constructing the entire bus matrix and predefining the fault boundary conditions. Moreover, the new method is robust and can be used to analyse the simultaneous faults as well. Finally, the proposed method was programmed in MATLAB and different scenarios were tested on an unbalanced network. The calculation results were examined by the simulations, which verified the effectiveness of the new method. The new method can analyse whole-line fault in unbalanced networks with IIDGs connection, extending the current fault analysis methods and providing foundations for relay protection.