An overview of substation equipment monitoring and diagnostics: Part 1

An overview of the current options available to utilities to ensure high levels of efficiency and overall reliability through primary equipment maintenance programs, despite cutbacks in maintenance programs, is provided. The options available to deal with these conflicting interests include reliability-centred maintenance programs, base line equipment monitoring sensors, basic equipment monitoring algorithms for use at substations, intelligent electronic device integration for sensors, substation automation local area network technology necessary for equipment monitoring, and new time-based preventative maintenance systems. Reliability-Centred Maintenance (RCM) which also utilizes Failure Modes and Effects Analysis (FMEA) is the option most frequently chosen, since it does not require taking equipment out of service for maintenance check as time-based preventive maintenance systems do. Since RCM involves continuous on-line monitoring, utilities are able to move from a periodic-based maintenance schedule to a just-in-time maintenance program. Specifically, on-line equipment monitoring reduces inspection, maintenance, and failure-related repair or replacement costs; enhances system reliability; provides better planning for scheduled outages; helps defer planned upgrade or replacement capital costs; reduces insurance premiums; and retains the knowledge of skilled staff through its expert system features. RCM uses FMEA and risk assessment techniques to identify and select maintenance tasks directly related to high-criticality failure causes. Consequently, risk analysis that permits the ranking of maintenance tasks to be performed, is an integral part of RCM. Quantitatively expressed, risk is the product of the chance of an event occurring and the impact of such an event. Risk-based analysis can be useful in determining which stations and which primary equipment should be monitored for which failure modes. 2 refs, 32 tabs., 3 figs.