Linli County Low-voltage Distribution Network Planning

The electricity distribution system and user are most closely related in electric power system. The electricity distribution system has direct effect on reliability and quality of power supply to user. The optimization of electricity distribution network would save a huge investment and operation expense for the power company as well as improve degree of satisfaction of user to power supply. The electricity distribution system planning becomes significantly important in the competitive power market. The essay describes the compilation principle of short-term (2010-2012)and long-term electricity distribution network planning(2012-2020)in Linli county.Pursuant to 11th five-year rural power network construction and reformation technology principle of Hunan Electric Power , combined with current power network and actual development status of the county, based on 11th five-year planning skeleton of national economy and social development of Linli county and 11th five-year and 2020 development planning of power network of Linli power supply bureau, the medium-low voltage electricity distribution network of Linli county is planned depending on 35kV-220kV main network frame of 11th five-year and 2020 development planning of power network of Changde power network (Approved text). The proposed planning target: build up a county electricity distribution network of strong grid structure, distinctive wire connection, complete power supply & distribution functions, excellent assets performance, and make it into a scientific & rational, safe and reliable networkWhich has realized economic and social benefits.Basic idea of planning: analyze status of power network, forecast power load and electricity quantity, compile feasible project and form it into an economic and efficient electricity distribution network to make the planning have significance of practical guidance.The essay firstly has analyzed the basic conditions of electricity distribution network in Linli County and raised the main problems. As the low automation of electricity distribution network of the county and difficulties in collection of load data, regression analysis and annual increment methods have been adopted to forecast the total electricity consumption. The field elasticity coefficient, field-divided forecast, per capital power consumption methods have been adopted during forecasting of segment load to obtain more practical forecasting. After forecasting electricity distribution network load and balancing electricity quantity, analyze the status and existent problems in details, raise ideas to solve the problems and make planning on the above basis. Aimed at the actual needs of user, divide the power supply segments with substation as the center and each 10kV line as basic unit. The planning covers power supply segment of each medium-low voltage electricity distribution network line, correct choice of line route, determination of interconnection and interconnection point location according to needs, rational distribution transformer stationing, correct choice of distribution transformer capacity and protection mode, measurement of distribution transformer district, remote metering, automation of distribution transformer, reactive power compensation of medium-low distribution network. Meanwhile, proper suggestions have been raised for automation of distribution network of Linli County.