Study On Distribution Network Planning With Distributed Generations Based On Improved Genetic Algorithm

Distributed generations (DG) are playing an increasingly important part in the future electric power system. Large amounts with various capacity of DGs connected to the distribution network will import a great effect on planning and operation in the conventional power network. Distribution system acts as an important role in power grid, especially in urban and rural region. Power supply reliability and the economic benefit rely on the distribution planning and construction largely.Based on the results of load forecast, distribution planning plays attentions on determining where, when and how to establish transmission lines to satisfy the power supply in the planning time. Under meeting the relative technical constraints, the objective is to decrease the construction cost and its operation economic. In fact, distribution power planning is a mixed and nonlinear integer problem in mathematics, where the optimization strategy is the main way. Acting as a modern heuristic global optimization algorithm, Genetic Algorithm (GA) is very good choice to solve the mixed problem, which has the advantage of no special constraints and objective functions in optimization problems.In this paper, after taking some constraint conditions into account, i.e., the limit voltage, radioactivity, convexity, power balance and distribution line operation limits, a series math objectives model for distributed grid planning including minimizing the construction and operation cost, is proposed. Then, based on the above models, the multi-objective models in distribution planning are introduced as well.GA is used to solve the models after comparing with the other intelligent optimization algorithms. As to the difficulty about describing the solutions, some modified methods are added to GA to enable it more suitable in distribution planning, which is called the Improved Genetic Algorithm method. At last, the models and algorithm is analyzed to a simple 25-nodes distribution system, and the results show the advantages.