Case Studies of Problems Diagnosed Using On-Line Machine Monitoring on Hydro-Generating Machines

On-line monitoring systems are valuable tools that provide information to help power producers get the most out of their generators in the safest and most economical fashion. Such systems can detect early signs of anomalies, allow planning of timely corrective actions, and ultimately prevent generator failure. Proven technologies designed for monitoring air gap, vibration, partial discharge, and temperature are available to assess hydroelectric machines under any operating and transient conditions. Rotor-stator air gap can be significantly affected by a host of factors, i.e. mechanical, thermal, and electro-magnetic. Monitoring the air gap reveals a great deal about the structural condition and dynamic behaviour of a hydro-generator. Combining data from air gap and other parameters through an integrated machine monitoring system allows comprehensive analysis of machine condition and behaviour. This information is valuable for effective operation and maintenance. The field experience case studies in this paper show examples where such combination of air gap data and other generator parameters has helped the power producers to better manage their generating assets.