The Simulation Research Of The Gas Flow Field And Rotating Magnetic Field For High Voltage Circuit Breaker

Power industry is a pillar industry of the economy development in China. Theconstruction and the development of higher performance, higher reliability and higherstability power system is a key to solve the contradiction between the supply and theelectricity demand. As an important control and protection equipment in the high voltage(HV), extra high voltage (EHV) and ultra high voltage (UHV) electrical power system, theHV SF₆ circuit breakers (CBs) are the dominant switchgear. And the HV SF₆ CBs take thekey role in maintaining the stability and the reliability of the entire power system. Theanalyses on the gas flow field and the influence considerations in the arc quenchingchamber for the HV SF₆ CBs, cover many subjects, such as, electricity, magnetism,thermodynamics, mechanism, and the likes. And it is one of the key problems for the studyon the dielectric recovery characteristics and the interrupting performance.The research object is the structure of a 550kV HV SF₆ CB, and the combinedsimulation calculation model between the SF₆ CB mechanism and the chamber isestablished according to the field characteristics with compressible, viscous, active andvariable boundary. And the whole field numerical analyses are made to the gas flow fieldin the chamber by varying the pressure/stroke characteristics provided by the operatingmechanism with finite volume method (FVM). Moreover, the changes of the flowparameters in the chamber are also comparatively analyzed under different pressure/strokeconditions. Furthermore, the corresponding pressure observation points, which are set atdifferent regions around the break and the nozzle, for obtaining the quantitative descriptionof the pressure changing with the opening stroke. From the simulation results, it can beobtained that, establishing enough pressure at the upstream of the nozzle is the key tointerrupt the CB successfully, and the dynamic changes of the pressure affect the flowparameter of the interrupting process directly.Based on the analyses above, for effectively controlling the gas flow and improvingthe blowing ability, a rotating magnetic puffer type of combination arc blow is proposed and for improving the blowing efficiency of the opening fracture during the interruption, akind of rotating magnetic generator is also proposed, setting between the movable and thefixed contacts. To control the gas flow generating by the rotating magnetic fieldintroducing by the magnetic field generator, and make it possible to draw the gas flow intoa spiral in the magnetic field generator, and with higher speed rotation movementcharacteristics, 3D field has been numerically computed and analyzed with the finiteelement method. And a rotating magnetic field with the same frequency changing with theapplied current has been obtained, and the gas flow suffered by the dual impaction of thegas and magnetic blow has been simulated, to effectively control the gas flow, and toimprove the interruption capability and dielectric recovery characteristics.