Abstract: An on-line monitoring system for partial discharge of generators was introduced, which was based on the Very High Frequency (VHF) measuring technology and the time-delay identification anti-interference principles. The anti-interference methods applied to this system were analyzed. Considering the application experiences on site and the experimental analysis, the test results and anti-interference capacity were verified. Techno-economic analysis shows that the establishment of such system is conducive to improve the safe operation and the economic benefit for power generation units.

Key words: hydro-generator, partial discharge, on-line monitoring, Very High Frequency (VHF)