665 / 2017-05-24 13:12:57

Bezier Curve-based Shape Optimization of SF6 Gas Circuit Breaker to Improve the Dielectric Withstanding Performance for both Medium and Maximum Arcing Time

bezier curve,Gas circuit breaker,3975,multiple arcing time

This paper presents the optimization to scheme to improve the interruption performance of a gas circuit breaker, which must do the interruption duty within specific arcing time for successful operation. The systematic process of design optimization was proposed by using the Bezier curve and sequential approximation technique for satisfying both medium and maximum arcing time. Depending on the specific arcing time, the position of moving parts is changed and the changed position directly affects the gas flow in the circuit breaker. Consequently, this flow change affects the temperature, pressure, density, and flow rate between electrodes and tank, which determines success or failure in the interrupting operation. To satisfy the design criteria for successful interruption, it is necessary to satisfy more than one arcing time at the same time. The diameter and the shape of the nozzle in the circuit breaker is a key part in securing the pressure rise resulting from the heated hot gas in the chamber. Thus, the nozzle shape design requires high expertise and proficiency. To solve this problem, we used the finite volume fluid in cell (FVFLIC) for flow analysis and the Bezier curve for fitting nozzle shape. The control points in the Bezier curve were selected as design variables and the optimization process was performed employing the sequential approximation technique. Based on the experimental results, the consistency of the optimization results was confirmed, and finally we will analyze the relationship between the fixed contact at each arcing time and the inflection point of the downstream of the nozzle.