Abstract：In order to solve the problem of low accuracy of small substation fault diagnosis，a small substation

fault diagnosis model based on cooperative game and cloud model was proposed. By analyzing the characteristics

and causes of faults，the diagnosis index system was established. Entropy method and expert weighting method were used to obtain index weight，cooperative game method was used to calculate consistency coefficient and combination weight，and the final fitting weight was obtained through normalization. Through the cloud model，the quantitative expression of each index was realized，and the weighted deviation degree was obtained. According to the weighted deviation degree，the final diagnosis result was determined. The experimental results show that the index weight distribution of the established model meets the consistency requirements，and the diagnostic accuracy of fault location and degree is high，which can provide more guarantee for the safe operation of substation.

      Key words：cooperative game；cloud model；small substation；fault diagnosis model；entropy method