Parameter Design Of High Voltage Circuit Breaker Model Machine Arc-quenching System And Flow Analysis

As the important switching equipment in the energy internet, circuit breaker is thedefender of the safety, reliability, stability and efficiency of the power system. Combiningthe empirical formula and numerical simulation, the high voltage SF6arc quenching chambermodel is proposed. Based on the GB standard and the corresponding design parameters, theenergy separation nozzle contour is designed.Based on the interrupting performance,insulation and safety characteristics of the circuit breakers in GB standard, the main parts ofthe arc-quenching chamber, shell structure and seal structural parameter in circuit breaker aredesigned. Moreover, the numerical analyses of the model have been obtained. The mainworks of this thesis is as follows:The arc extinguishing system, the parameters of housing and the seal in the modelcircuit breaker are disigned. It covers the design of structure parameters of the static contact,the nozzle, the pressure cylinder, the shell, the static seal ring, the static seal groovedimensions and size of the dynamic seal, and the design and calculation of structureparameters of the self-type moving contact, the air guide channel of moving contact, thesupport tube of pressure cylinder, the static side shield, the fixed side shield. Moreover, inthe design process, the shunt capacitors, switching resistors and the selection of adsorbentsare taken into consideration. And the average opening speed, contact opening distance andstroke are designed.According to the principle of the separation of energy, the nozzle is designed for the252kV SF6circuit breaker, and the model of the energy separation effect has been simulatedusing the finite volume method. And the simulation results shown that, in the process ofbreaking, before interruption, pressure difference varies smoothly and velocity holdssmoothly. After interruption, pressure difference increases greatly and velocity decreaseslargely. In addition, based on criteria such as Rafael theorem, different elevation downstreamnozzles structural model has been simulated using the finite volume method. And thesimulation results shown that, along the nozzle from the upstream to downstream direction,the pressure difference, the density, the temperature gradually decreases. At the junction ofthe throat and downstream, they are minimum. Then along the downstream direction, theygradually increase. Velocity gradually increases. At the junction of the throat and downstream, it is a maximum. Then along the downstream direction, it gradually decreases.And the pressure difference distribution, the density distribution, the temperature profile andthe velocity profile of nozzle with downstream elevation cotangent value of6have moregradual change than one of nozzle with downstream elevation cotangent value of4.