To improve the performance of fault processing in distribution networks, an approach of multiplication of auxiliary contacts arrangement with two-in-three principle is proposed to improve the correctness of switch state detection. The approach of correcting the errors of switch states based on the correlation of electrical telemetering information is described. A unified method based on Bayes evaluation to improve the robustness of fault location for interphase short circuit, single phase grounding and fault location of low voltage distribution networks on account of the trouble call information is put forward. An example of single phase grounding location is given to illustrate the proposed approach, showing its feasibility and effectiveness.