Development of a stationary partial discharge monitoring system for high-voltage rotating machine stator windings

The stationary partial discharge detector developed by the Bureau of Reclamation provides an economical method of monitoring partial discharge activity in high-voltage motor/generator stator windings. No physical connection to the stator coil or winding is required for this monitoring system; therefore, the integrity of the winding insulation is not compromised. The system can be used to monitor partial discharge during normal online operation so that readings reflect the actual steady-state running conditions of the winding. Rising levels of partial discharge activity can provide an early warning of insulation deterioration, permitting repairs before serious damage or an in-service failure occurs. Results of the application of this technique to the stator windings of Unit G-19 at the Grand Coulee Third Powerplant are presented