Circuit allocation in subtransmission switching substations using best-first search strategy

Based on the best-first search strategy, this paper develops a general computational model for the automatic determination of circuit allocation schemes in subtransmission substations. Starting from a discussion of the allocation requirements, fault indices based on the percentage of power rating loss of circuits are first derived. The best-first strategy is then defined by the group allocation and overall allocation index trees, which are formed from the relations of the fault indices. A search procedure implementing this strategy is developed to determine the best overall allocation arrangement, which is found by combining the best group allocation schemes. A general method for assigning interconnectors to the tasks of source and load circuits to assess the security level of the overall allocation schemes in the process of islanding constraint checking is reported. The model is implemented by a logic programming language, Prolog. The developed software system is applied to allocate six groups of circuits from seven substations to a 132 kV duplicate-busbar substation.