A Novel Method of Suppressing VFTO in GIS –Spiral Tube Damping Bus-bar

This paper presents a novel method which is called spiral tube damping bus-bar to suppress VFTO (very fast transient overvoltage) in GIS. The suppressing mechanism of the new method to restrain VFTO is analyzed. And the structure characteristics of damping bus-bar is introduced as well. Furthermore, a 550kV GIS test platform is set up to check the mitigation effect of the damping bus-bar. The experimental results show that the damping bus-bar exhibits excellent suppressing effect of VFTO, which can attenuate the maximum amplitude of VFTO from 2.42p.u. to 1.49 p.u. And the number of SF6 gas breakdown and its duration also decrease dramatically. The measurement results also reveal that damping bus-bar has another favorable ability which can restrain the high frequency component of VFTO. All the superior performance of damping bus-bar indicate it is a method with broad prospects and bright future in engineering application.