Implementation Strategies And Practice On Distribution Network Planning In Medium And Small Cities

As the terminalsystem of the power systems’supply grid, distribution network directly affect the power quality of the majority of electricity users.To improve the safety and reliability of network operation,andensure economic,scientific and reasonable of power grids, distribution network must be optimized for scientific planning. Taking county of Hcity planning of distribution network,research load forecasting, order decisions of planning, planning optimization design and effectiveness assessment.This paper described conventional load forecasting method in detail,for example, method ofexperts predict, method ofconsumption, method ofthe natural growth coefficient, method ofelastic coefficient,method ofload density, method ofmaximum load utilization hours, time series forecasting, regression analysis and forecasting, fuzzy prediction, neural network forecasting method, gray prediction law, substation load forecasting method. Analysis prediction model advantages and disadvantages of various methods and scope,and proposed a improved combination method based on mutual checking load. The method is based on common historical and current situation data grid,appropriate forecasting model and weights, and the results obtained were several prediction methods are checked, and ultimately get the forecast results. This method is scientific, reasonable and feasible after the county of H city load practice.On the limited investment fund condition, an reasonable arrangement and rebuilding sequence of the distribution grid planning and construction will provide an scientificthe guarantee. The article introduces the analytic hierarchy process and it puts forward that based on the AHP construction of medium voltage distribution grid and modification idea and process. It sets the medium voltage circuit as an example,to establish a hierarchy medium voltage circuit diagram, and to calculate its unqualified function model. Besides, it needs to calculate the unqualified reduced value. According to the expert opinion to structure the matrix and index weight. Through the calculation and test, we can get the computed result of urgent degrees. According to the investment scale and the ranking result of urgent degrees, we can determine the optimal improvement plan. Thereby, the science of rebuilding sequence decision-makingcould be increased effectively. It has been verified by the instance, and this method has a strong practicability.Based on the present situation of the power grid in the county of H city and the load forecasting results and the decision-making method of planned project & rebuilding sequence,we put forward the optimization design and assessment method of the small and medium cities urban distribution grid planning project. Firstly, according to the situation of power grid and load forecasting results, and combining with the results of superior power planning, we can make the design from these three aspects, the new lines of substations, remolding medium voltage distribution grid, remolding low voltage distribution grid. We also can getmore details of analysis on the necessity of the construction, development scheme, the effect of implementing. According to the investment scale and application of the AHP, to determine the rebuilding sequence of the project and the optimal planning scheme. Besides, we can make a planning result evaluation through the reliability and the economy aspects. The evaluation results show that, the planning scheme is scientific, reasonable, and have stronger engineering practice & promotional value.