Simulation Test on Suppressing VFTO in UHV GIS with Magnetic-rings

An approach for suppressing VFTO in UHV GIS with magnetic-rings was presented,and a series of simulation tests were carried out.The test system was constructed with a 252 kV GIS,and travelling wave with high steepness was generated by a SF6 gas gap.The tests under 50 kV,75 kV and 100 kV were implemented to verify the suppression effects of R2KB ferrite and FJ37 amorphous magnetic-rings with different length to the amplitude and steepness of the voltage traveling wave.The tests results show that the suppression effect on the amplitude of the voltage travelling wave will not remarkably change when the length of the magnetic-rings is not shorter than 0.5 m,while the steepness will decrease along with the increase of the length of the rings.The ferrite rings have a better suppression effect than amorphous ones when the length of the magnetic-rings is not shorter than 1 m.The tests results indicate that it is feasible in principle to suppress VFTO in UHV GIS with magnetic-rings,and ferrite rings should be preferentially selected.