抄録
When a configuration of distribution system is radial, a load of every customer is served from single distribution substation. Therefore, a fault that takes place at the distribution substation causes every load in the system out of electricity. Then, it is required to supply electricity from the neighboring distribution networks to the faulted network by modifying the on/off status of circuit breakers (CB) within the faulted network and tie-lines that can connect the faulted system and the neighboring networks. For finding a new configuration of distribution system, following constraints should be checked: a configuration of distribution system must be radial, no overload in any line occurs, every customer should be supplied electricity or the number of customers without electricity should be minimized. In order to find the most desirable configuration, many cases of combinations of the on/off status of CBs are formed as candidates that should be checked if they satisfy the aforementioned constraints. Since many numbers of CBs are implemented in actual distribution system, it may be impossible to check every candidate because it takes very long computation time. In order to shorten the computation time, this paper proposes approaches with some criteria by which procedures checking the constraints is terminated during processing for finding solutions and also the number of candidates to be checked if they satisfy the constraints is reduced. Numerical examples carried out for a system with 30CBs. The total number of candidates that will be formed by using every combination of CBs is 230 (≒ 1.0 × 109). The number of candidates that are checked by the proposed method is 6158 that is about 1/180000 of the total number of candidates. In addition, solutions obtained by the proposed method accorded with those obtained by using every combination of CBs. This shows that the number of candidates that can be checked within a limited time will be increased greatly by using the proposed method.
