Methods And Techniques Of Power System Fault Diagnosis Based On Petri Net Theory

With the development and expansion of modern power system, the demanding on the transmission line's safeoperation and the reliability of power supply is increasingly high. However, for some reasons, the power system especially transmission network maybe interrupted inevitable. To improve power grid operation, the research on fault diagnosis of power system has been one important task.Fault diagnosis based on traditional Petri net is restricted due to the increasingly complex operation modes and flexible protection configuration. In view of the limits of traditional Petri net theory in fault diagnosis, a practical Petri net model based on relay protection space-time setting values is proposed, which can simulate the coordination among different protective relays more accurately. In application of possible fault components set and fault components connection diagram, the model can quickly adapt to variations of power system operating modes. In this thesis, applied framework of power system fault diagnosis is established and fault diagnosis algorithm based on Petri net is studied combining with actual system. Fist, the relay configuration of actual power grid is arranged and recorded in the database. Then several typical faults are analyzed. Finally, the algorithm is programmed and validated in the Petri net simulation environment. The results illustrate that in the case of simple faults or faults with incorrect operation of relay and circuit breaker, the proposed method can quickly and precisely locate fault components and analysis results according to credibility. This method can be applied to the grid for on-line fault diagnosis.According to the character of fault diagnosis, aiming at practicability, the Petri net technology which is good at describing discrete event dynamic system is applied to fault diagnosis in this thesis, and it is in possession of academic and actual use.