Lightning overvoltages in low voltage networks

The European Standard EN 50160 "Voltage characteristics of electricity supplied by public distribution systems" indicates that in low voltage power systems the transient overvoltages between line conductors and earth will not exceed 6 kV peak, but higher values occur occasionally. Some generic information is also given about the rise times of the overvoltages and their energy content. Amongst the different causes of overvoltages in LV power supply systems, lightning has a prominent role when the MV and LV lines are overhead. This paper intends to give a contribution to the knowledge of the rate of occurrence, wave shape and energy content of lightning originated overvoltages. Additionally, the paper indicates which aspects of the supply system design have a major influence on the above overvoltage characteristics.