Investigation On Mechanical Property Of Operating Mechanism And Insulation Performance Of Arc-quenching Chamber For SF₆ Generator Protection Circuit Breaker

With the increase of the electrical power system and operating reliability, it is very necessary to research and develop the generator protection circuit breaker and investigate the corresponding key technical problem. In the electrical power system, the generator protection circuit breakers are applied to protect and control the main circuitry of the generator.In this thesis, by means of the application of electro-magnetics, mechanical dynamics, hydrodynamics, numerical technology, and the computer science, based on the combination of the conservation law of energy, Bernoulli equation and gas flow property, the coupled numerical model of the operating actuator and the arc quenching chamber for the puffer SF₆ circuit breaker has been established. And the programming of VB6.0 has been employed for numerically analyzing the mechanical and electrical property of the circuit breaker. The operating characteristics, the pressure and gas flow characteristics under no-load condition has been obtained. Moreover, the key technical specification, such as oil pressure, piston diameter, mass of the moving system, volume of various pressure chambers, diameter of nozzle and pressure chamber, charging pressure of the arc quenching chamber have been numerically computed and analyzed. Furthermore, the arcing time and the mechanism of the effect of the interrupting current on the gas flow and pressure in the whole interrupting course have been studied. And for improving the insulation performance of the circuit breaker, the computation of the electric field for the 18kV SF₆ generator protection circuit breaker has been performed using the finite element method. The dynamic variations of the distribution of the whole domain of the electric field under different opening stroke have been numerically simulated. By closely combining the operating mechanism and the arc-quenching chamber, the interaction of the interrupting and gas flow simulation have been realized. By the comparison between thenumerical simulation and experimental, the theoretical foundation for researching and developing the generator protection circuit breaker has been provided.