Lightning overvoltage performance of 110 kV air-insulated substation

• Lightning overvoltage performance of 110 kV air-insulated substation in hydro power plant.
• Station surge arresters with different rated voltages and energy classes were considered.
• Application of line surge arresters for the improvement of the lightning performance of substation.
• Lightning parameters derived from lightning location system observations around 110 kV substation.
• An algorithm for the assessment of the lightning flash multiplicity was developed.

This paper presents an analysis of lightning overvoltage performance of 110 kV air-insulated substation connecting hydro power plant with the rest of the power system. The demonstrated procedure includes the application of a three-dimensional electro-geometric model of transmission line entering the substation, description of modeling process and EMTP simulations. Different overvoltage protection schemes were discussed including station surge arresters with different rated voltages and energy classes. The installation of line surge arresters on the first towers of the transmission line entering the substation for the improvement of the lightning performance of substation was analyzed.Lightning parameters derived from lightning location system observations around 110 kV substation were analyzed and compared to ones used in literature and calculations. For this purpose an algorithm for the assessment of the lightning flash multiplicity was developed in order to determine the current amplitude probability distribution of the first and subsequent cloud to ground strokes. Energy absorbed by surge arresters due to multiple strokes was determined and an optimal overvoltage protection scheme was proposed.