Research On Reactive Power Optimization Mode Of Rural Distribution Network

Reactive power optimization (RPO) of distribution network is the effective measure to improve the voltage level, reduce network loss and ensure the safe and economic operation of grid. Our country has extensive-coverage country-level electric power networks, electricity quality of which is generally not ideal and the situation of network loss is serious. Thus, the study on the RPO of county-level power grids is of great practical significance.A reactive power optimization method for whole rural distribution network was proposed, which divided whole distribution network into three levels, i.e., high voltage level, medium voltage level and low voltage level, in accordance with its own features each sub-network was re-divided into optimum units. The reactive power optimization of each optimum unit was implemented by improved ant colony algorithm. In the meantime, relevant RPO model was established based on this method, in which objective function was distinguished between high voltage level and medium-low voltage level.After a mathematic model of the whole distribution network had been built, the power flow algorithm was analyzed based on the structural feature of the distribution network, and at last back and forth method was selected as our power flow algorithm. This method had high calculating efficiency and superior convergent property, which was tested by node system.On the basis of the comprehensive analysis on a summary of reaetive power optimization algorithms, ant algorithm was adopted as the optimization algorithm of the paper. Ant Colony Optimization Algorithm is a heuristic search algorithm based on probability selection, which fits for solving the reactive power optimization problem of distribution network. The basic ACOA often gets into premature stagnation during evolution and is difficult to explore other solutions in the neighbor space. And a Dual Population ACOA was presented to deal with it. Referred to the individual diversity feature in genetie algorithm, the algorithm separated the ants into two populations which evolved separately and exchanged information timely. Under the comparison and test with the test function, the result showed that DPACOA had a higher application value which had more superior optimization results to the original ant colony algorithm's. A complete realization scheme was given, which applied the DPACOA to the field of reactive power optimization of distribution network, and the program was applied to the actual system to verify the feasibility of itself. In order to develop a RPO system which should meet the actual requirements, corresponding practical solutions were constituted. Besides, system structure was also studied and designed and the functions of the main modules were determined. The design would lay the foundation for the engineering realization of RPO. Finally, an application program was developed, which was applied to actual rural distribution network on the reactive power optimization. The optimization results indicated that program presented in this paper was feasible.