Comparing On-Line Partial Discharge Monitoring Solutions For A Critical 6.6 kV Motor

Medium Voltage (MV) and High Voltage (HV) asset criticality is increasingly at the forefront of plant operator’s goals, with a view to preventing unplanned outages and maximizing uptime. Condition monitoring is integral to truly understanding asset condition and allowing remedial works to be scheduled and conducted at the most convenient times. In particular, on-line Partial Discharge (PD) monitoring of such motors and generators remains the best early warning indicator of stator winding insulation degradation. The authors present utilization of the latest On-Line PD monitoring technology, through a recent real-world pilot project conducted in South East Asia on a critical 6.6kV 9000HP Motor, whereby a combination of different sensors and locations were organized over an intensive 8-week period. The data from this pilot project is presented, including de-noising techniques and Phase Resolved Partial Discharge (PRPD) patterns for different sensor installations, concluded with a discussion as to the pros and cons of each solution. At the center of this pilot project is the goal to ensure technical performance of each sensor solution and improve the cost of ownership, particularly for installations where retrofitting sensors and providing communication can be challenging.