Importance of Capacitance on Metal Oxide Arrester Block Model for VFTO Applications

Presently, due to several factors, metal-oxide arresters find very limited applications against very-fast transient overvoltages (VFTOs). To enhance the utilization of these arresters and to meet the needs of the dynamic performance of arrester under VFTOs, an improved model for the prorated block is proposed and its performance is analyzed by applying current surges of different front times (5 ns to 8 μ s), tail times, and peak values. There is a time lag between the residual voltage and discharge current due to block capacitance. The delay thus observed in the initial peak of residual voltage is experimentally verified.