Continuous and Remote Monitoring of Partial Discharge in medium voltage switchgear

This paper is based on two decades of experience with continuous monitoring of Partial Discharge (PD) on medium voltage substations and other equipment. Simple and proven technology uses multiple sensors distributed along a line-up. It allows for additional noise reduction and for localizing of PD activity sources. The importance of continuous PD monitoring vs. periodic PD measurements is discussed considering that PD activity can be very unstable and highly dependent on ambient conditions. Negative periodic PD tests in equipment can result in a false sense of security. Case studies from field experience are presented to support the discussions. Advances in communication and computing have allowed Remote Monitoring and Continuous Monitoring to become very effective combinations to make sense of Partial Discharge diagnostics relieving owners of the burden of data analysis for intricate PD diagnostics. Alarms can be detected and analyzed in near real-time, and previously overlooked pre-failure conditions can be detected to avoid a critical failure. Remote data collection is safe and secure, experts are readily available. Portals and web pages provide easy access to accumulated data for customers.