A new model of power grid fault diagnosis and its corresponding solving methodology are proposed. By taking the real-time action state of the prospective faulty equipment

the protection equipment and the circuit breaker in the blackout area as the optimization variables

a multi-objective optimization model is built based on the maximum difference between the expected state and real state of protection and circuit equipment as well as the maximum difference between the real-time state and the corresponding alarming information. Fuzzy optimization technique is adopted to achieve the optimal matching of optimization variables. The dimensions of variables are greatly reduced to get rid of the “curse of dimensionality” of other approaches. At the same time

the difficulty of choosing the weighting coefficient is avoided by using the multi-objective and fuzzy optimization technique. Finally

the efficiency of this new model is verified by case study.