Study Of Three-Dimensional Field Simulation Analysis And Structure Optimum Design For Long Vertical Forced-Air Isolated-Phase Bus

Electric power is the bottleneck of economic development, and it must be firstly developed in the national economy. Looking ahead 30 years, for the development of the electric power system in China, it is necessity to develop the hydroelectric and the nuclear power generation system with energy saving, environmental protection, and high efficiency. For both electricity generation methods, the generator is generally located at 100 to 200 meters deep underground, however the transformer is located at ground. Consequently, the long vertical segment enclosed bus connected between the Generators and the transformers is the key component. Because the basic theoretical research is relatively inadequate in China, the design and production of foundation is lack of experience, and the product is currently rely on imports (and there exist a small amount of Chinese-made products within 50 m).In this thesis, the temperature and gas flow model has been proposed and derived based on the finite volume method, and the numerical computation has been performed. Then the distributions of the temperature and the gas flow have been obtained. Moreover, the three dimensional electric field has been computed and simulated. And the distribution principle has been investigated. And the theoretical basis for insulation design and structure design has been provided. And the optimum of the enclosed bus has been realized using the optimization method.The investigation results show that, the field distribution of the long vertical segment enclosed bus is non-uniform. The maximum electric field strength is at the connection between the insulator and the conductor. And the insulation design should be improved for the above region in order to avoid the insulation breakdown. Based on the computation and simulation of the three dimensional temperature field and gas flow field for the long vertical segment enclosed bus under different cooling conditions, the novel forced air-cooled scheme is proposed, which apply the wind blast for the middle phases and the wind re-flow for both sides phase. Moreover, the corresponding distribution of the temperature and flow field has been given out in this thesis. The higher temperature rise and possible electric failure for the ends of the middle phase can be solved using the proposed scheme. Furthermore, the feasibility of the design has been verified based on the comparison of the numerical simulation and the sub-analytical results. And the validity of the optimum results has been proved by the Comparison with the actual products.