The ferrite ring

as a potential new mitigation method

is of interest to UHV grid operators for its simple structure and competitive cost. However

the current knowledge of the new method is far from mature for practical application. This dissertation conducted researches on the application conditions and installation location of ferrite rings. The relationship between the VFTO amplitude and negative reflection coefficient of the circuit is studied

and the negative reflection coefficient of different components and structures in the GIS circuit is quantitatively analyzed

a structure in 3/2 wiring-mode substation and operation mode which may produce high-amplitude VFTO is clarified

i.e.: symmetrical T-shaped structure constituting both-side open circuit. It is found that the main application of the ferrite ring is to suppress the symmetrical T-shaped structure of both-side open circuit

and recommended mounting position of the ferrite ring is given.