Study On Decision-making Of Dual-voltage Distribution Network Considering The Temporal And Spatial Distribution Characteristics Of Load

As an important section of electric power system,distribution network,which links superior power source to user terminals,has direct effects on users' power safety,reliability and supply quality.At present,the pattern of “heavy generation and light distribution” in China's power grid construction has led to serious losses in the distribution network under the single-voltage level distribution mode,which has led to the fact that the operating costs of traditional distribution networks have remained high in turn.Selecting the appropriate dual-voltage power distribution method and adding a suitable supplementary voltage level will help reduce the operation and maintenance costs of the low-voltage and medium-voltage distribution network,but increase the investment and construction costs and the failure costs at the same time.Therefore,it is necessary to fully understand the loss and its distribution characteristics as an important part of the operation cost in dual-voltage distribution network planning,accurate ly consider the operating costs,and comprehensively measure the overall economic benefits.The research and decision on the dual-voltage distribution method and the supplementary voltage grades have good reference for the scientific regulation and optimization of the distribution network while verifying its rationality.The variety of load on the low-voltage side of the distribution network and its different space-time characteristics directly affect the loss and its distribution characteristics of the dual-voltage distribution network.In addition,the short-term,medium-term and long-term planning are inseparable from the full grasp of load characteristics.While it is not appropriate to use the load level in the same period as the basic data simply.Therefore,depending on the season interval,the relatively representative load levels can be selected respectively as the typical load datas for reference.After fully studying the loss characteristics of the dual-voltage distribution network that takes the temporal and spatial distribution characteristics of the load into account,an optimization model of the dual-voltage distribution network planning decision-making considering the operational economy is constructed.Which provides a theoretical reference for making precise distribution planning decisions considering the temporal and spatial distribution characteristics of the load.The main contents of this paper include:(1)By reviewing the current situation,the principle and structure of dual-voltage distribution are studied,and the connection mode and wiring system of supplementary voltage layer are analyzed.The importance of studying the distribution characteristics o f network loss as an important part of operating costs is clarified.(2)Aiming at the problem that the daily load data acquired by the existing methods may not be representative,a nuclear density optimization method is proposed.Based on the relevant load data that is relatively closer to the actual situation,this method can be used to select the relatively representative load data for each time period of the representative month.Then the loss characteristics and the law of time of the dual-voltage distribution network with load-time characteristics are studied.Based on the above study of the time characteristics of loads,a dual-voltage distribution network that accounts for the spatio-temporal characteristics of the load is studied based on the spatial distribution characteristics of the load,and the applicability of the dual-voltage distribution method is described.Research based on the relative load data that is relatively closer to the actual situation and taking the spatio-temporal characteristics of the load into account will help to describe the loss characteristics and laws of the dual voltage distribution network relatively accurately.(3)Based on the nuclear density optimization method,taking the space-time characteristics of the load into account,a tabu search planning optimization model of a dual-voltage distribution network with a large number of planning schemes is constructed.The model takes the time value into account and uses the present value of the total cost of investment construction costs,operating costs including the power loss cost caused by network loss considering the temporal and spatial distribution characteristics of the load,as well as failure costs as the objective function,with reliability and safety indicators as constraints.Through the tabu search method applied to the model,the power distribution planning scheme of the dual voltage distribution network is optimized.The effectiveness of the proposed method and model is verified by examples.