Computation Of Insulation Performance And Study Of Nozzle For 800kV Extra High Voltage SF6 Circuit Breaker

With development of the electrical power system, high voltage transmission power system becomes the new development trend. And the demand for security, reliability, stabilization and validity of circuit breaker (CB) has been brought forward. Moreover, it is important and significant to research and design the high voltage class large capacity SF6 CB for increasing the transmission efficiency of power system and improving the transmission quality. The analysis of insulation performance based on the electric field numerical computation is the key problem for investigating the dynamic insulation performance of high voltage CB. Due to the nozzle plays very important role, which greatly influence the breaking and closing performance for SF6 CB, and the nozzle is the important part for determining the interruption performance.In this thesis, according to the technical requirement, voltage level and the initial design structure, for satisfying the manufacturing technical condition and engineering requirement, the numerical simulation of the electric field and analysis of insulation performance for 800kV double-break tank type SF6 CB has been studied. Within the arc-quenching chamber, the nozzle and contact is axisymmetrical structure, however, there exist the shielding cover, the whole computation domain of the electric field in the arc-quenching chamber is actual three dimensional (3D). Aiming at the structure characteristic, 3D mathematical model of electric field of the arc-quenching chamber has been established. And the electric field has been numerically calculated using the finite element technology. Moreover, the simulation results for different opening stroke has been obtained and analyzed. Besides, the axisymmetrical mathematical model of electric field for the bushing of SF6 CB has been established and computed for determining the insulation structure of the bushing. For the results of simulation and the test, the rationality for designing the insulation structure of the 800kV double-break tank type SF6 CB has been partially verified.The breaking and closing performance is the fundamental and most important investigation task. In this thesis, the technics, manufacture, computation method and pressing-sinter process of nozzle material have been studied, tested and analyzed. Furthermore, the theoretical and design foundation for the extra high voltage SF6 CB has been provided.