Abstract
This paper has analysed the reliability importance of power line communication (PLC) system connected to the Nigerian national electricity grid for a period of eleven (11) years. Bimbaum's component importance technique is used to derive the components' reliability, importance functions of phase-to-earth, phaseto- phase and inter-system PLC couplings. A comparative analysis is made on the oomponents' reliability importance of the existing PLC system in the power Holding Company of Nigeria (PHCN), phase-to-phase and inter-system networks. The study has shown that the components' importance of PLC systems is a function of the coupling methods. The outputs of the analysis are then compared, with suggestions and recommendations made.