AN ON-LINE PARTIAL DISCHARGE monitoring system has been recognised by R&D Magazine in the US as one of the 100 most technologically significant new products of the year.

HydroTrac detects the onset of equipment failure problems in hydrogenerators. Developed as a collaborative effort between epri, New York Power Authority (NYPA) and Iris Power Engineering, it is claimed to offer a less expensive and less labour-intensive approach to partial discharge testing than traditional portable instrumentation.

‘On-line diagnostic systems improve the probability that hydroelectric units will be available when called upon to generate power,’ said Jan Stein, EPRI’s generator project manager. ‘HydroTrac is a reliable instrument for measuring key partial discharge analyser (PDA) quantities.’ Most hydrogenerator outages are caused by stator winding insulation failure due to age, mechanical malfunction or stress. The traditional approach to checking equipment condition is by utilising portable PDA instrumentation. These are connected to sensors embedded in the stator winding, and data is taken to help assess machine insulation at that instant in time. However, in order to obtain accurate PD trend data, many measurements must be taken at various times under similar operating conditions. This entire process is labour-intensive and the cost can be significant. HydroTrac, according to the developers, has revolutionised the process by providing affordable, continuous, real-time information on the condition of the generator to help avoid costly in-service machine failures and allow plant personnel to plan corrective action.

‘As a major hydroelectric producer, the New York Power Authority is pleased to be at the forefront in developing and demonstrating this innovative technology for plant monitoring,’ said Shalom Zelingher, NYPA’s director of research and technology development.

‘We plans to deploy the HydroTrac at our major hydro facilities, including the St Lawrence-Franklin D Roosevelt and Niagara power projects. This will help facilitate planning and implementation of our maintenance activities.’ EPRI is seeking members to help demonstrate HydroTrac and collect ‘lessons learned’ from several installations in order to make the system more robust and require minimal customisation. This project is open to domestic and international organisations interested in the development of a cost-effective, condition monitoring system for hydroelectric units.