It is well known that as height
increases with voltage rating, the voltage distribution is
more non-uniform because of presence of the stray
capacitance and can be improved by addition of grading
rings. In order to model the complete arrester assembly
(without or with grading rings), it becomes necessary to
compute block and stray capacitances with housing
accurately. Finite element method (FEM) is used to
calculate the accurate capacitance values [19–25]. The
computed block and stray capacitance values are used in the
modelling of metal oxide arrester for VFTO.