Research On Power Grid Fault Diagnosis Method Based On Extended Analytical Model

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 and circuit breaker condition assessment with power grids fault diagnosis. The main work is as follows:Based on the state evaluation of relay protection and circuit breaker, an extended analytical fault diagnosis model is proposed. In the extended analytical model, the relay protection and circuit breaker condition assessment are considered, and the failure confidence values of the protection and circuit breakers are introduced into the analytical model as a logic variable, providing effective evidence for the false-operation or fail-operation of relay protection and circuit breaker.Based on the extended analytical model, the fault hypothesis measure function is established. The complete set of fault hypothesis is obtained using variable length chromosome genetic algorithm. Through the selection of the optimal fault hypothesis, the setting principle of the weight of each logical variable is studied, and the accuracy of fault diagnosis is improved. 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.