Differential and common mode propagation in PLC low voltage networks

This paper deals with switching between differential and common mode propag ation in Power Line Carriers on low voltage distribution networks. A large field test involving several thousand items of equipment was initiated in 1 995, which revealed unexpected results on network environments. An approach to the mode conversion mechanism is explained here. Moreover, experimental measurements confirm the assessment of the amplitude of the phenomena. The common mode propagation in Power Line Carrier (PLC) systems introduces ext ernal influences from two directions: telluric currents on one hand, and si gnificant electromagnetic field radiation on the other. Such fields have be en both simulated and measured. The consequences of these phenomena are two -fold. Firstly, PLC signals from LV networks cross its environment resultin g in the disturbance of others in the neighbourhood. Secondly, it makes ele ctromagnetic compatibility an issue which cannot be neglected.