Feasibility study of maintenance cost reduction in redundant customer delivery systems

Maintenance is carried out on various transmission system components to keep their performance within acceptable standards and to maintain their average life expectancy. The cost associated with maintenance work is largely dependent on how often maintenance routines are performed and on the level of work to be done. Current maintenance routines on transmission system components are normally performed in accordance with equipment manufacturer´s guidelines and modified by field experts as maintenance experience is gained. The implementation of the reliability-centred maintenance (RCM) in the electricity industry has reengineered the maintenance practices and has resulted in a significant saving to the industry. One area where an additional maintenance cost saving can be made is the customer delivery system with a redundancy in supply. In this system, the loss of one supply path would not adversely affect the reliability of supply to customers. By doing less frequent maintenance on one or both supply paths, some cost saving can be made without jeopardizing the reliability of supply to customers. This paper describes the study that was performed recently at Hydro One to assess the impact of reduced component maintenance cycles on the reliability´ of redundant customer delivery systems. A cost/benefit analysis was performed to determine the possible consequences of reduced maintenance and to decide whether or not to stretch out the component maintenance cycle