Study On Optimal Switching Devices In Electrical Distribution Networks Of Guiyang Southern Power Bureau

Electrical Distribution Networks (EDNs) are connected directly with customers and have great influence on the quality of power supply (including reliability). It was counted that 80% of the total customer interruptions around resulted from EDNs. So, it has become a focus to do research on the optimal configuration of EDNS for the supply quality improvement. Presently, the optimal configuration of EDNS includes two types, i.e. network reconfiguration and optimal switch devices, and this paper will do some research on the latter one. That is ascertain the number and fixing location of load switches, breakers and fuses to make sure the investment is minimal under the conditions of flow, reliability and etc. In the paper, flow calculation is realized by the improved forward-backward sweeping method, reliability evaluation is realized by the fault spreading algorithm and optimal switch devices are realized by the idea of immune algorithm. This paper is mainly as follows:(1) Improving EDNs lay-dividing model. EDNs are characteristic of radiation configuration and high values of R/X so that forward-backward sweeping method is widely used in its flow calculation. Lay-dividing model is an effective measure to realize forward-backward sweeping method.The presented model can divide EDNs nodes into some lays effectively and take any node as root node to search forward and backward so that the forward-backward sweeping method of EDNs flow calculation and the fault-spreading method of EDNs reliability evaluation can be easily realized.(2) Reliability indices, basic formulas and reliability evaluation algorithm for EDNs based on fault-spreading-method are introduced. Reliability evaluation program is applied in RBTS-BUS6 test system and Dusi substation's 10 kV EDNs.(3) A model based on immune algorithm for optimal switching devices (OSD) in EDNs is proposed. The model for OSD based on average yearly value, which considers the investment, maintenance and outage costs, is proposed. This problem is formulated as a constrained, non-linear optimization problem with non-differentiable objective function. The solving algorithm based on immune algorithm(IA) for OSD is proposed. The optimal number and position of switching devices, reliability, investment and outage loss of EDNs can be determined by the proposed algorithm. IA is proved to be good convergence and quick convergent speed by the numerical results.(4) Applying the model for OSD based on immune algorithm into EDNs of Guiyang...