Study On Modeling And Decision-Making For Transmission Expansion Planning

With the development of electric utility reformation, electric power utilities are carrying out revolution on price bidding and separation of transmission and generation in China. Transmission planning is encountered with brand-new external environment. Traditional transmission planning methods and models can not meet demand of the deregulated electricity market. Generation planning uncertainty and increased load uncertainty, and reasonable decision-making method are the two difficult problems to be solved in transmission planning in a deregulated electricity market. In order to scientifically plan the transmission network and meet the increasing load demand, the suitable transmission planning model and method are urgently required, and transmission planning scheme is necessary for scientific decision. Therefore, this dissertation chooses transmission planning modeling and transmission planning scheme decision-making under deregulated electric power system as the main research contents.This dissertation establishes an uncertain transmission planning model to cover the uncertain factors of electricity market on transmission planning. This model describes the uncertainty of load and generation injection by fuzzy number, solves the superiority planning scheme set based on membership, and brings forward the decision-making method of uncertain transmission planning based on expansion feasible of transmission line unit. It can meet the demand of generation and load as much as possible.This dissertation describes all segments of transmission planning on mathematic, and then yields the process of making decision. The decision-making process can be divided into two kernel steps according to two-step transmission planning method: form superiority planning scheme set and decision-making. This dissertation establishes the model on forming superiority planning scheme set for two-step transmission planning method. It normalizes and models the transmission planning decision-making, and provides the foundation of scientific decision-making.This dissertation quantitatively evaluate the adaptability of transmission network planning scheme to generation expansion planning and load increasing based on the branch-node real power sensitivity. The branch-node real power sensitivity can guide newly additional generation and load to connect with transmission network.Since transmission planning is a multi-attribute decision problem under deregulated electric power system, this dissertation brings forward technical and economical integration evaluation for transmission planning, and establishes a set of indexes for integration evaluate. The integration evaluate method ascertains the weight of very index based on the maximal indexes differentia of every planning scheme. It can roundly evaluate the transmission planning scheme.With the practical situation of load sustained growth and construction cost swift growth in China, this dissertation puts forward the modified multi-stage transmission planning considering the rapid growing load level and increasing construction cost, the rapid growing load level will ahead consider in transmission planning. This modified multi-stage transmission planning model increases the adaptability to load and reduces the risk in construction investment, and reflects the newly connotation of proper leading development planning on transmission network under deregulated electric power system.In the aspect of model solving, this dissertation modifies the basic particle swarm optimization algorithm by chaos ergodicity and vaccination immune mechanism. This dissertation put forward the chaotic immune-vaccine particle swarm optimization, and applies it to solve transmission planning model. It can avoid getting into local optimum, speed up the convergence rate, and improve the accuracy of convergence.Case systems show that these presented models and decision-making methods of this dissertation are feasible and effective.