Maintenance Cost Reduction for Electrical Power Distribution System in Refinery using Reliability-Centered Maintenance Technique

This research carried out maintenance cost reduction for electrical power distribution system in a refinery using reliability centred maintenance (RCM) technique. Exponential reliability method was employed to analyse the electrical power distribution system failure data to determine the reliability metrics of the electrical power distribution system which generated the proposed reliability-centred maintenance plan for the critical electrical power distribution system equipment in the refinery. Linear programming was employed to develop a mathematical model that predicts and optimizes maintenance requirement for the electrical power distribution system based on the analyzed reliability metric. The reliability of the electrical power distribution system was analysed and the results showed that, out of the six (6) components that make the electrical power distribution system in the refinery, pins and disc insulators had the highest reliability with 69.27% and power transformers had the lowest reliability with 7.31% during the period investigated. The formulated linear programming model was solved using LINDO software, and the fifth iteration produced an optimal solution of: x1 =2.67, x2 = 1.67 and F = 2,800,000 naira. The optimized maintenance labour force gave that approximately 3 engineers and 2 technicians should be employed for the refinery electrical power distribution system maintenance task to spend a minimum of N2,800,000 naira as cost of salaries and wages for the labour force monthly, and N33,600,000 as cost of salaries and wages for the labour force annually. The current labor cost (N187,200,000 /year) decreased with respect to the optimized maintenance labour force (N33,600,000/year), The proposed linear programming maintenance model results indicate a saving of about 82.05% of the total annual maintenance labor cost as compared with that of current maintenance labor (RTF) plan for the refinery electrical power distribution system. Conclusion and recommendation were made that the reliability centered maintenance and linear programming technique applied in this study were effective in providing means to reduce maintenance cost of electrical power distribution system taking both the refinery operators and the power suppliers into account when performing asset management, and as such should be adopted by refinery stakeholders to reduce maintenance cost of their production system.