Comparison of metal-oxide surge arresters circuit models and implementation on high-voltage transmission lines of the Hellenic network

The transmission lines of high-voltage networks are protected against lightning strikes and internal overvoltages with the use of overhead ground wires and surge arresters. The appropriate modelling of a power system´s components is a significant issue, in order to obtain reliable theoretical simulation results for the lightning performance of the line that will be used in the design of a new line or the improvement of an existing one. Metal-oxide surge arresters present difficulties in their modelling owing to their dynamic characteristics, which depends on the rise time of the injected impulse current. Several equivalent circuit models have been proposed in the technical literature for the adequate simulation of this frequency-dependent behaviour. The current paper presents the most important surge arresters models, comparing the residual voltage that each model extracts for different lighting currents. For each model, the arresters failure probability is computed implementing them on Hellenic high-voltage transmission lines, performing a sensitivity analysis for the tower footing resistance and the arresters interval installation.