The importance of correlating dynamics when performing partial discharge measurements and analysis

Online measurement and assessment of partial discharges has proven to be an effective tool in evaluating the condition of insulation and thereby limiting unscheduled outages. Yet, dynamic factors such as humidity, load, and temperature have a significant effect on PD levels. In the past, this data has not been collected simultaneously with PD measurements - something best done on a continuous basis such that correlation and trends can be revealed. This work will show that the best assessment of insulation condition is based on correlating dynamic environmental and load conditions with PD levels and then trending this information over time. This process will result in superior diagnostics and thereby improved maintenance and outage decisions. Actual data collected from rotating equipment and switchgear will be presented and discussed.