An Assessment Method For Power Supply Capability And Coordination Of Distribution Networks

Terminal grid distribution network is powered directly facing the user, the structural characteristics comprising a plurality of voltage level, the voltage level of the distribution network can safely and reliably supply will directly affect the quality of power supply to the user. Distribution network capacity plays an important role for distribution network planning, reasonable evaluation with supply capacity and distribution network to ensure adequate power supply margin for safe and stable operation of great significance. This article aims at propose a comprehensive evaluation model about power supply capacity and coordination for multi-voltage distribution network, the comprehensive evaluation models include load supply capacity, network infrastructure level, technical level of equipment and coordination of supply, considering the impact of distributed power supply evaluation system, using fishbone diagram, theoretical Delphi, AHP, fuzzy comprehensive evaluation method for analysis and solution, find the distribution network capacity constraints, provides distribution network about operation, planning and transformation a new theoretical tool.This paper describes the main factors of the evaluation index distribution network and supply capacity of the basic theory, find each use fishbone diagram method from the power supply reliability rate, line loss rate, voltage passing rates and equipment utilization index in four effect categories power supply capacity of the main factors, the factors are classified, summarized, concluded that the establishment of the power supply capability evaluation system, consider multilevel distribution network coordination. The paper added some new index into the evaluation system, such as distributed power capacity rate, substation capacity coordination, transmission capacity coordination, load balance coordination, combined with supply capacity index, constitute a comprehensive evaluation system. Fishbone diagram analysis was used to identify the main factors of supply capacity, AHP was used to establish evaluation system and Delphi to fix index weights. AHP establish an evaluation system structure, and the judgment matrix constructed using the Delphi method, were indicators of empowerment. Use Curve Expert curve fitting tool for fitting score, establish a smooth index score mathematical formula.Actual regional power supply capacity and coordination assessment study to identify bottlenecks in the regional power grid power supply, and weak links proposed rectification, to provide a reference for the distribution network planning and transformation.As the increases proportion of distributed genertator to distribution network, its power quality, security of supply, network planning have caused some impact, so the power supply capability evaluation increased consideration of distributed power. This paper discusses the impact of the distribution network to power supply capacity and coordination, select an area load power supply case, applications to build evaluation system, select nine related evaluation, in accordance with the target layer, criterion layer, factor level, the program level to build a comprehensive evaluation system. For the shortcomings of traditional analytic hierarchy process, a new method making AHP better which based on triangular fuzzy numbers and definition of possible degree will be brought forward and achieved by a Matlab program. Finally calculate the possible degree and score of comprehensive evaluation about three programs.The final results obtained sort quantify the optimal power supply solutions and programs are programs containing distributed power supply scheme for optimum load.The research on evaluation system is verified to be effective and reasonable by a network planning example, it can also be seen in detail in contrast computing AHP and triangular fuzzy AHP process.