Research On Novel Interrupter Structure And Mechanism Of The Vacuum Circuit Breaker

With the increased transmission line voltage and the improved system capacity, higher insulation requirement is proposed for the high voltage electrical equipment. And fine insulation equipment directly affects the operation, the security and the stability of the overall power system. As one of the most important electrical devices in the power system, the high voltage vacuum circuit breakers (VCBs) must have higher reliability.Multi-breaks in series is applied in the design of the extra high voltage VCBs. Because of the existence of the coupling and transient variation of the multi-physical fields, the multi-breaks in series is the uniformed large space time field system covering the multiple physical parameters. And the insulation performance for each break in the series system change a lot than one break case, and the investigation on the unknown factors is necessary. Based on the application of the EHV VCB applied in the system, the dynamic insulation coordination property covers the dynamic insulation of each break and the design of the multi-breaks in series. In this thesis, 3D electric field of the triple-breaks vacuum interrupter (VI) in series is numerically simulated using finite element method (FEM). And the location of the maximum electric field strength and the field distribution along the surface of the movable and the fixed contact are calculated and figured out. By the comparative analyses with different insulation structures in series, the variations of the electric field strength are obtained and illustrated. Moreover, by introducing the shielding covers and parallel capacitors, the design of each 72.5 VI unit is accomplished and the insulation property of the 220kV triple-breaks in series EHV VCB is analyzed.Furthermore, a novel arc blowing mechanism using the rotating magnetic field is presented in order to improve the interrupting performance of the VCB. And based on the above analyses, a disc rotating magnetic vacuum extinction chamber is designed, and 3D mathematical model of the magnetic field is proposed. Using FEM, the internal magnetic field characteristics of arc region for the VI is numerically simulated and calculated. And the arc energy dissipation is accelerated by the rotating magnetic field, which is conducive to rapid arc extinguished, the ablation of the contact is reduced and the life of the VCB is extended.Based on the analyses of the rotating magnetic field, combining with the rotating magnetic arc blow principle, horizontal magnetic arc blow and longitudinal magnetic arc blow, the horizontal disc rotating magnetic blow VI and a longitudinal disc rotating magnetic blow VI are designed. Meanwhile, two sets of coils coaxial stacking method is used, and a certain angle in the axial is staggered to form two different groups of rotating magnetic field in time and space to enhance the role of the rotating magnetic field.