Electric power systems face an ever-growing penetration (PV) and other microgeneration as well as non-linear loads such as electric vehicles. This is a common link between these : the extensive use of power electronics converters. These devices are a source of medium-to-high frequency harmonic distortion and their impact on the local distribution grid must be carefully assessed in order to evaluation possible network unbalances, demaging power line resonance conditions, transformer core saturation and overhearing.