Transmission Network Planning Program Evaluation Based On LCC Theory

As an important part of power system planning, transmission planning is important work to safeguard the stable development of power system. Firstly in the current transmission planning, a few competitive feasible schemes are generated based on part of constraint conditions which can be quantified more easily. Then each alternative should be examined and selected according to all the constraint conditions. The evaluation value of each scheme should be calculated, and finally the strategic decision is made in virtue of comprehensive evaluation method. Therefore, the study of transmission planning program comprehensive evaluation method has important theoretical and practical significance.Based on technical considerations, traditional transmission planning program evaluation takes network reliability and other technical indicators as the test conditions which must be met, and then chooses the optimal solution which has least investment cost. This traditional evaluation idea doesn't quantify the technical indicators such as reliability, and places little consideration on the operation and maintenance costs after the completion of the transmission network. So the coordination of planning program between economy and reliability can not be achieved.Considering the drawbacks of the traditional transmission planning program evaluation methods, the LCC theory is introduced to solve the comprehensive evaluation of transmission planning scheme in the paper. Based on the cost breakdown of the transmission planning program, the LCC model can be established, which can be divided into investment costs, operation and maintenance costs and waste disposal costs, and other parts. Considering the poor applicability of the analogy estimation and engineering estimation method, the parameter estimates based on fuzzy number theory is introduced to calculate the LCC of transmission planning scheme, which provides evaluation method in the aspect of economic indicators.In the transmission planning program evaluation and decision, it need not only to consider the economic issues, but also to analyze and compare the performance factors such as grid reliability, grid security, load adaptability, operational flexibility. Therefore, the cost-effectiveness evaluation model based on the REC indicator system is established in this paper. Besides the LCC indicator which is calculated above, the risk and performance of the transmission planning scheme are quantified. By means of the model, a more comprehensive decision-making result can be given for the transmission planning scheme.Finally, by means of organic combination between theory research and project needs, the alternatives of the 12th Five-Year Plan of the transmission grid in certain province are placed into the technical and economic comprehensive evaluation, and finally the optimal alternative is selected.