Study Of Transmission Network Planning Based On Multi-objective Theory And The Planning For North-channel

Applying the power system technology, power market theory and economics principles, the methods and theory of transmission network planning is studied. Combining with West to East Power Transmission Project which includes the electric power transmission to Beijing-Tianjin-Tangshan Power Network, a multi-objective transmission network planning model that considering the investment of program, the reliability costs of transmission system and the environmental benefits is led in. Then the paper analyzes and compares the cost of different way of transmission.To begin with, the paper introduces the theory of transmission network planning which is the foundation of the study under traditional environment as well as the electricity market environment. And it also discusses the electric equilibrium of supply and demand, the voltage level and power transmission mode, the option of transmission capacity and the techno-economic analysis of transmission project as the theoretical foundation of transmission network planning. Secondly, by using cost-benefit analysis principles and the theory of outage cost, a concept of power transmission interruption cost is led in to describe the degree of reliability of transmission system. Then according to the investment of transmission lines, the reliability cost and the constraint of system power flow, a model of transmission network planning is proposed. It turns to multi-objective programming theory to optimize the weight coefficient of the model and makes some improvements to the genetic algorithm model. With the mathematical model and algorithm that have been proposed in the paper, the author makes the computing program by using Matlab to achieve the goals above and the model is used in the example of IEEE18 nodes planning system. It's feasible in practice to use the improved model and the accuracy of results is much better than before, so is the running speed of the model. Fourthly, the paper proposes the concept of effect cost of comprehensive environmental to figure out the influence on the investment of transmission programs of the land occupied cost of transmission corridor, the corona discharge cost as well as the response capacity for extreme natural disasters, and points out the quantitative method. Finally, according to the North-channel power transmission of "West-East Power Transmission" project, this paper adopts the power supply-demand index model and combination load forecasting model to predict the load level of Beijing-Tianjin-Tangshan power grid by the year 2010, 2015 and 2020. In the planning, it accounts and compares the cost of all the parts of different methods of power transmission (including 500kV AC, 750kV AC,±800kV DC and 1000kV AC). In the end, a transmission planning of Beijing-Tianjin-Tangshan power grid is given from the method of life-cycle costs.