The optimal switching operation of distribution systems with stochastic load models by object-oriented programming

This paper solves the optimal switching operation considering the stochastic load models by object-oriented programming for the Distribution Automation System in Taiwan Power Company. The attributes of 4-way line switches in the underground distribution network are defined to store the information of switch on-off status, current loading, phase voltage, and the up/down stream line switches. With the object-oriented programming, the distribution network configuration can be easily identified by connectivity trace according to the line switch status. The current flows of line switches can be updated when the optimal switching operation is performed to balance the loads on feeders and reduce the risk of overloads. The optimal switching operations perform the load transfer among the feeders and main transformers to achieve the load balance and loss minimization. To support these functions more effectively, the stochastic load models of service customers are derived. The probabilistic load flows of line switches are solved by the stochastic power system analysis. The dynamic load behavior can be included in the derivation of optimal switching operation. The binary integer programming incorporated with probabilistic load flow is proposed to help system operators determine the optimal switching operation and to balance the loading of feeders. The current flows of line switches and feeder configuration are updated according to the switching operation. The practical distribution system feeders are selected for computer simulation to demonstrate the effectiveness of the proposed methodology to solve the optimal switching operation.