Overvoltages on the low voltage distribution networks. Origins and characteristics. Consequences upon the construction of Electricite de France networks

Overvoltages on the LV distribution networks can be classified into two types, temporary and transient. The most important transient overvoltages mainly originate in a lightning stroke occurring either on the MV network side and which propagate throughout the LV network via the MV/LV substation or near to an LV network. Electricite de France currently limits the temporary overvoltages on LV conductors to 1500 Vrms according to the regulations in effect. With regard to transient overvoltages, studies and experiments carried out enabled proving that they are generally below 8 kV and might, given certain configurations, be as high as 14 kV excepting any direct lightning stroke