Transmission Network Optimization Planning Considering Risks

As a major ingredient of electric power system planning, transmission network programming, on the basis of the existing power network, mainly aims to choose appropriate circuitry expansion so as to achieve the optimization in the safe operation and economical efficiency of the electric power system. With the increasing construction pace of national interconnected power system, west-to-east power transmission system, and north - south mutual supply system, network interconnection is expanding increasingly on a large scale. China plans to accomplish the large interconnected power network nation wide which is safe and reliable, meets the requirements of electric power transmission, and satisfies the demands of marketable operation in order that resource allocation and optimization and social benefits maximization can be realized. A proper transmission network acts as the foundation for the power system to run safely, stably and economically. Therefore, it is profound and pressing to study transmission network expansion and programming as a subject.In the traditional vertical integration system, transmission programming, based on load forecasting and electricity generation programming, usually takes only one possible future vision into consideration. After the reform of electric power market, power network programming is confronted with more and more uncertain elements which bring new challenges. In order to deal with these uncertainties, new measures and tools are needed. This thesis, through applying Monte Carlo analogy to handle the uncertain elements in power market environment and using the uncertainties of power flow to describe the uncertain factors brought by power generation and loading, establishes a transmission network model that can take uncertainties into account.The power transmission system established under an electrical market environment was faced with greater challenges. More unpredictable uncertainties would lead to risks including investment risks and security risks. Therefore, it is of great importance to evaluate and analyze the cost and risk of the power transmission system programming. This thesis, using chance constraint's risk denotation and basing itself on risk factor, establishes power transmission system model which considers risk constraint. In addition, this thesis aims to assess system risk further, and uses quantification risk assessment fee to show the cost caused by the risk under the market environment. As a result, a comparison between the risk expense and investment expense becomes obvious. Emulation indicates that both safety and economy can be achieved in this way.Global search algorithms is a profoundly effective method to solve the complicated nonlinear optimization problem of power network programming using genetic algorithm. However, during the formation of population initiation, crossover and mutation, genetic algorithm will give rise to a great deal of infeasible solution and cause other problems such as prematurity, non-bandwidth convergence, and low convergence speed as a result of coding problem. On this, this thesis aims to introduce niche genetic algorithm which is based on replacement mechanism and makes some improvements on the problems still existing in genetic operation.In the last part, this thesis makes a full and comprehensive analysis of the present situation and future development of Shandong power network, and based on the development of power supply and loading center of Shandong province, this thesis makes some optimization programming for Shandong 500KV power network adopting programming method and solving method mentioned. Through the analysis of the programming scheme, it has the capability to satisfy the demands of the power supply development and loading requirements of Shandong province. Moreover, it does not only ensure economic operation, but also favorable security and stability.The programming method mentioned in this thesis is feasible as it can take the practical project into consideration and accomplishes a scientific and reasonable spatial grid structure, which is of great reference value.