The Robustness Degree Evaluation Of Distribution Grid Structure

As the rapid development of china’s national economy, and the significant growth of the power load, in order to adapt to the rapid development of the city, the State Grid Corporation proposed the establishment the robustness and smart grid of excellent asset、excellent quality、excellent service and excellent performance, power gridrenovation and expansion is in full swing in the country. Because of the early unreasonable grid construction planning, or the excessive consideration of economic sexual, the current distribution network structure is relatively fragile, that malfunction caused by line overload is the common problem. Under the background of the robustness power grid construction, the robustness sexual of the overall grid is affected by the robustness sexual of the distribution network, as distribution network is directly connected to the user; therefore, the robustness sexual assessment of distribution network structure becomes the imminent task.This paper defines the consept of distribution network structure robustness degree, based on the flow calculation, from the perspective of "margin" and "network anti-destruction ability", and proposes the evaluation system of the distribution network structure. Analytical Hierarchy Process characterizes the difference between the different evaluation factors quantitatively and depicts the hierarchy between the evaluation factors clearly. In this paper, analytic hierarchy process principle is used to determine the level of assessment factors in the distribution network structure robustness evaluation system. The network anti-destruction ability of the grid is designed as one of the the factors of the grid robustness degree evaluation, to examine the grid topology security, from the perspective of the degree of network nodes association. On the other hand, if robustness degree of Grid structure is good or bad, is often fuzzy; the fuzzy membership function of robustness degree of each assessment factors is established, based on fuzzy analysis theory, which quantify the fuzzy problem and descriped the robustness degree of Grid structure quantitatively. Finally, through the analysis of the example, the analysis process of robustness degree assessment of the distribution network structure is descriped, which verify the feasibility and effectiveness of the evaluation system and its method.