A Study on Surge Over-Voltages in a Smart Grid

This paper has investigated switching surge overvoltages, i.e. closing surges, fault surges and fault clearing surges in a smart grid based on EMTP simulation results. The simulation results show that looped configuration of distribution lines tends to produce a lower overvoltage, while straight system configuration generates the highest overvoltage. Among various switching surges, a closing surge produces the highest overvoltage and a fault clearing surge produces the lowest one. When a wind farm is connected to the distribution line, the switching overvoltage is lower than that in a system with no wind farm. The above observation has indicated that a closing surge simulation can be carried out neglecting wind farms from the viewpoint of insulation coordination of the smart grid.