Study On Power Grids Complex Fault Diagnosis Method Considering Relay Protection Condition Assessment

With the build of smart grid, the continuous enhancements of the interconnectedness of power grids and the interactive requirements with users ask dispatching center to have a great ability to diagnose complex power grids fault effectively. Aiming at complex fault, this paper studies the diagnosis model and the objective function, and combines relay protection condition assessment with power grids fault diagnosis. The main work is as follows:Considering the requirement and characteristics of power grids fault diagnosis model, based on the function modules of relay protection, an online relay protection condition assessment structure is proposed. To follow the change of assessment parameters, a variable weight fuzzy synthetic evaluation is proposed. Based on the online assessment structure, the method assesses the failure mode of relay protection with variable weight fuzzy synthetic evaluation and fault tree analysis. The failure mode of relay protection would be the new logic variable of power grid fault diagnosis model.To diagnose the power grids complex fault effectively, a power grids fault diagnosis method considering relay protection condition assessment is proposed. The method builds power grids fault diagnose model considering the result of online relay protection condition assessment. Based on the fault diagnose model, an objective function is constructed. The result of relay protection condition assessment is added to objective function as a modification. And the modification could verify if relay protection has false-operation or fail-operation. Based on the fault diagnose model, the method searchs for the optimal solution using genetic algorithm with variable length chromosome. Finally, combined with the above research results, a practical online power grid fault diagnosis system is designed. The effectiveness and practicability of the system is verified by the offline tests and online running.