Coloured Petri nets approach for solving distribution system contingency by considering customer load patterns

Typical customer load patterns, which have been derived by a load survey study, are used to determine the daily load profiles of each service section of distribution feeders. The hourly current flows of line switches and distribution feeders are solved by three-phase load flow analysis over a daily period. For a distribution contingency such as feeder overload or short circuit fault, the artificial intelligent coloured Petri nets with best-first search approaches are then applied to find the optimal switching operation decision. A coloured Petri nets model with inference mechanism is derived for load transfer among distribution feeders after the overloading feeders have been identified or the faulted section has been isolated. To determine the effectiveness of the proposed methodology, a Taipower sample distribution system, which serves a mixture of customers, is selected to perform the computer simulation. By comparison with the conventional Petri nets, the proposed coloured Petri nets can significantly reduce the size of network models, and a more effective switching operation plan can be designed by taking into account the load characteristics of the customers served.