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Research On Reactive Power Planning On 10kV Feeders And Transformers In Distribution Network

Posted on:2006-04-26Degree:MasterType:Thesis
Country:ChinaCandidate:Z XuFull Text:PDF
GTID:2132360155472774Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
Reactive power compensation in distribution network is an effective method to decrease power loss and improve voltage quality. To solve the shortage, inappropriate location and inefficient switching of reactive compensation equipment, suitable reactive compensation planning is necessary to obtain more social and economic benefit. Two aspects of reactive compensation planning are researched in this paper, in which one is the compensation capacity and banks planning in distribution transformer low-voltage side, the other is the optimal selection of compensation location on distribution feeders. The main contents are as follows. To avoid the inappropriate allocation and frequent switching of shunt capacitors, a new planning model is proposed, in which the dynamic control strategy based on the relation between capacitor switching and load variation is fully considered, and in which the objective function is to minimize the payback period and the action amount limit of capacitor switching in one day is adopted in the constraints. Because the investment benefit and the switching validity of compensation both are considered, the optimal model is more worthy in the practical application. The investment cost of compensation equipment is imprecisely simplified as the function of the capacity in traditional methods. In this paper, the function is modified according to the actual cost of the capacitor size, banks (switches) and additional controller in the compensation equipment. Thus the investment cost of equipments is made more practical and the economic estimation of the planning scheme is made more reasonable by using the new formula. Due to the discrete nature of the proposed planning model, a genetic algorithm (GA) is adopted to solve the problem. In GA, an integer encoding technique is presented, by which the action amount limit of capacitor switching is automatically satisfied during the process of population initialization, crossover and mutation operations. So the searching efficiency of GA is improved. The problem of concentration and overlapping of the compensation location often occurs by the traditional selection methods. To solve the problem, a new index of Bus Power Moment (BSM) is presented and the BSM method for searching compensation location is proposed. First, the whole 10kV feeder is divided into several areas by using the BSM index. For each area, there is only one reactive power supply and the index of BSM is almost equal to each other. Then, the compensator location in each area is finally determined through further searching with the condition of minimum BSM. Because the proposed method is based on the principle of reactive power balance in each area, the locations of compensators is selected more reasonable and effective. Based on the data of lines, transformers and loads in 10kV feeder of practical distribution network, a lot of simulations demonstrate the efficiency of the proposed models and algorithms.
Keywords/Search Tags:distribution network, reactive power planning, genetic algorithm
PDF Full Text Request
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