Hot-Spot Hunting: Experience with Online Partial Discharge Analysis as a Tool for Predictive Maintenance for Medium-Voltage Switchgear Systems

OVER HALF OF NORTH-AMERICAN INDUSTRIES ARE EXPERIENCING EVEN greater requirements for up-time and reliability while reducing maintenance costs and scheduled outages. We often find that, in today's market, preventive maintenance and testing of electrical distribution equipment has been extended well beyond historical time periods or those recommended by the original equipment manufacturers. One method to address increasing up-time while reducing maintenance outages and costs is to perform more online predictive diagnostics. A well-known, traditional online predictive tool has been the thermograph survey. Thermography observes temperature, or hotspots, in the line of sight of the instrument. Partial-discharge (PD) analysis is the newest technology being applied to medium-voltage (MV) electrical equipment, and, in contrast to a thermograph, it can detect corona or surface tracking behind the metal barriers associated with MV equipment.