Revista de sistemas eléctricos y electrónicos

Influence of Arrester Parameters on Overvoltage Characteristics on Protected Transformer

Abstract

Abugalia A

Different protective devices types based on previous literature are discussed. Special attention is focused on metaloxide
surge arresters, their non-linear characteristics, models, factors affects on protective characteristics, effect and
behavior in working conditions. The paper presents the analysis of the influence of non-linear characteristic of protective
metal-oxide arrester on the overvoltage shape appeared on the protected transformer. The characteristic of the arrester
is approximated by power type function. As an example the overhead transmission line connected to transformer
through a busbar is considered. The line is characterized by their surge impedance and travel time and the transformer
by its surge impedance. The transformer is protected by protective device such as metal-oxide arrester connected in
parallel with it. The system of equations describing the overvoltage transmission line, transformer and the protective
device modeled by non-linear v-i characteristic, based on digital step-by-step solution is written. The computer modeling
software is used to solve the equations and compute overvoltage’s waveshape at transformer. The (v-i), (v-t), and (i-t)
characteristics obtained as the result of these computations are presented.