A single-line-to-ground fault diagnosis method in small-current-grounding system based on fuzzy-integral decision fusion technique

With the purpose of improving reliability and adaptability of SLG fault diagnosis, a diagnosis method based on fuzzy-integral decision fusion technique is proposed in this paper. The method firstly constructs a criterion set which covers all types of commonly used criteria for SLG fault diagnosis. And through comparison between criteria's application scope and DN's actual status at fault moment, confidence degree for each criterion is obtained and converted into fuzzy measure distribution in criterion set. On this basis, according to fault characteristics, criterion in the set is respectively used to do SLG fault diagnosis, and fault measure is generated from each criterion. Afterwards, the fault measure is fuzzy-integrated about fuzzy measure in the criterion set to realize effective integration of multiple diagnosis results and obtain more reliable conclusion for SLG fault diagnosis. Simulation shows that, under various conditions of different DN neutral-point grounding modes, different initial fault voltage angle and different fault resistance, this method could always locate fault line accurately no matter whether the local diagnosis results are consistent or not.