Fuzzy Timing Petri Net for Fault Diagnosis in Power System
Figure 8
The backward FTPN model of Figure 6 for fault at 275 kV north busbar of Kapar substation. The marking state of FTPN indicates the postfault condition. Places , , , and correspond to main, local backup, remote backup, and breaker-failure relay, respectively. Token in place indicates that the main relay (87BN HI) has been operated and its signal has been received. Receiving signal from circuit breaker CB8 is shown by a token in places and . Receiving signal from circuit breaker and CB7 is shown by a token in places , , and . The broken lines are the routes of the FTPN in its firing sequences.In the case of tripping circuit breakers, places designated by trip get token, and in the case of nonoperation of any , places the indicated by Ntrip would get token. OP means that the main relay has operated and NOP means otherwise. Transitions , , and are sink transitions and would fire if the main relay and breakers CB8 and CB7 have operated, respectively.
