A micro grid fault diagnosis method based on redundant Petri net considering temporal constraints

As more and more distributed generations are connected to the grid, the features of micro grid, are no longer the same as conventional grids. A micro-grid fault diagnosis method based on redundant Petri net considering temporal constraints is put forward in this paper. Firstly, a tripartite criterion for fault location is proposed on basis of Wide-area information protection method. Secondly, The Petri net model is divided into fault locating layer and fault clearance layer by hierarchical modeling. Fault locating layer is built based on the tripartite criterion (current phase, amplitude and the DG current direction information). Fault clearance layer is built based on the logical relationship between protection and circuit breakers. Moreover, the transitions with timing constraint are defined. Thirdly, the alarm messages (relays and circuit breakers action information) collected from SCADA system are screened by temporal reasoning. Further, we carry out the matrix operations by means of redundant embedded Petri net to discriminate the malfunction or misoperation of the relays and circuit breakers. Finally, Finally, the validity of the diagnosis model and method is verified through a case study.