N-PE transmission system for Narrow-Band PLC

In this paper, a new signal transmission system for Narrow-Band Power-Line Communications (NB-PLC) has been proposed in order to solve problems of the conventional systems. The serious signal propagation loss was the problem for the differential-mode transmission system, which used the live and neutral conductors. Malfunction of the earth leakage circuit breaker was the problem for the common-mode system, which used the live, neutral and protective earth conductors. The proposing system injects and receives the signal between the Neutral and Protective Earth (N-PE) conductors. In order to compare the proposing N-PE transmission system with the differential-mode system, Packet Error Rate (PER) performances of 144 pairs of wall outlets for AC100V, which consisted of 78 in-phase pairs and 66 out-of-phase pairs, in the authors´ laboratory were measured. Although the 40% outlet pairs could not communicate at all for the differential-mode system, the ratio was reduced to 4% for the proposed system. Moreover, the communication quality of the PER value being less than or equal to 0.5 was improved 1.7 times more than that of the differential-mode system.