Analysis Of The Gas Flow Field And Optimization Of The Electric Field For The Auto-expansion Double Action 252kV SF₆ Circuit Breaker Arc Quenching Chamber

With the industrialization development in China,the power load is increasing,the power system developed steadily in ultra high voltage,large capacity and intelligent.The power lines of 220 kV voltage level which distributed and transmitted power has become the backbone network of China’s power system,formed a reliable power grid structure and turned into the aorta of power system.The requirement of safe and stable operation of power equipment is increasing,among which the most important one is the high voltage circuit breaker.The analyses on the gas flow field and the influence considerations in the arc quenching chamber for the high voltage SF₆ circuit breaker cover many subjects,such as,electricity,magnetism,thermodynamics,mechanism,and the likes.And it is one of the key problems for the study on the dielectric recovery characteristics and the interrupting performance.The research object is the structure of 252 kV auto-expansion double action SF₆ circuit breaker,according to the field characteristics with compressible,viscous,active and variable boundary.The auto-expansion double action SF₆ circuit breaker arc quenching chamber physical and mathematical model is established.The main work and research contents are as follows:1.The finite element method is used to simulate the two-dimensional axial symmetry structure of the arc quenching chamber,and the numerical simulation analysis of the static insulation performance is carried out,and circuit breaker in several different open distance static insulation performance are analyzed.Under different open distances,the electric field intensity distribution,the electric potential distribution and the electric field intensity vector at the position of the gate areobtained;2.According to auto-expansion double action 252 kV SF₆ circuit breaker gas flow characteristics,dynamic mesh and sliding mesh technology and user program UDF（User-Defined Function）has being used,the finite volume method and the control equations of combined solution has being utilized,the arc quenching chamber gas flow field simulation analysis of cold breaking case circuit breaker.The dynamic changes of the parameters of the arc quenching chamber,such as pressure,density,mach number and velocity,were obtained;3.The arc model of the equivalent element method was used to simulate the interaction between the arc and the gas flow field in the arc quenching chamber;The gas flow field pressure,temperature and mach number of the arc quenching chamber were obtained,and the distribution map of the dynamic change of the circuit breaker trip was obtained,the results are analyzed;4.According to the analysis results of the electric field,the electric field optimization was carried out.The electric field optimization is achieved by changing the shape of the contact.The optimization of the electric field in the arc quenching chamber is carried out by using the first order method provided by ANSYS itself.The optimization of the shape of the main contact and the arc contact is carried out.The electric field in the arc extinguishing chamber distributed more reasonable after optimizing the contact shape.