Distribution network reconfiguration for load balancing with a coloured Petri net algorithm

A rule-based expert system with a coloured Petri net (CPN) algorithm is developed for load balancing of distribution systems. CPN models of the distribution components such as four-way line switches are proposed to derive the proper switching operations. In this way, the loads on transformers and feeders will become more balanced. Heuristic rules based on the standard load transfer operation procedures of the Taipower distribution system are included in the best first search of the CPN to obtain the desired switching operations for load balancing. For the overload contingency during the summer peak season, load shedding is also considered in the CPN models to provide service to as many key customers and loads as possible. The priority indices of each feeder and service zone are determined in advance according to the key customers within the service territory. A Taipower distribution system with 68 feeders is selected for computer simulation to demonstrate the effectiveness of the proposed methodology. It is found that load balancing of the distribution system can be obtained very efficiently and the risk of overloads can be reduced by applying the proposed CPN model to determine the optimal switching operation.