Study On Economic Life Of Transmission Line Based On Life Cycle

With the development of power system and in-depth development of reducing the losses of electricity grid and energy conservation,the importance of transmission lines economically operation is becoming increasingly significant.In the past,in order to improve the reliability of transmission lines,there is a phenomenon of excessive maintenance,which leads to a huge waste of resources.Therefore,it is necessary to consider the reliability and economy of transmission lines,to study the relationship between the transmission line fault and the factors affecting the transmission line,to analyze and evaluate the transmission line,to calculate the life cycle of the line by using the theory of life cycle,and to formulate a reasonable operation and maintenance plan and to guide the transmission network planning,in order to improve the lean management level of electric power enterprises.This article first analyzed the factors affecting of transmission line fault,and the meteorological conditions,the components of the transmission line,the condition of the line operation and maintenance are divided into 4 first grade indexes and 21 two level indexes,and the evaluation system of the transmission line index is established.Taking the first level index as the criterion level and the two level index as the index level,and the FCE method be used to build the hierarchical structure model.The weight of each index is calculated by nine scale AHP method,and the membership function of quantitative index and qualitative index is determined by trigonometric distribution method and fuzzy statistical test method.Finally,the influence factors and the estimated value of line state are obtained by operation.In order to calculate the operation cost and failure cost of the line,the line fault is divided into three grades according to the influence of the fault.The particle swarm optimization is used to optimize the two parameters of the least squares support vector machine,and a PSO＿LSSVM based transmission line fault rate prediction model is established.The prediction model is used to calculate the I level fault,II level fault and III level fault respectively.On the basis of the whole life cycle theory,the LCC model of transmission line is constructed,and the annual average cost estimation formula of the transmission line is put forward,and the economic life of the transmission line is determined according to the minimum annual cost.In order to better compare the economy of transmission line transformation scheme,this paper further divides the cost of line in the transformation scheme,and puts forward a comprehensive cost calculation model for transmission line transformation.This model takes into account the partial dismantling or new situation of the line in the actual operation,and is carried out according to the line input and transportation.The cost is calculated year by year.The economic life prediction of the existing lines in the transformation scheme is carried out and used as the time node of line reconstruction.When optimizing the economic scheme,interval analysis is introduced to eliminate the calculation error caused by a single value and to better compare the merits and demerits of each plan.