Standardization of on-line VHF PD measurements on turbo generators

Based on field experiences on a number of different turbo-generators in the Netherlands, several fundamental and applied aspects of on-line very high frequency (VHF) partial discharge (PD) diagnostics are discussed. In particular the systematic results presented in this paper contribute to: 1. the characteristics of different on-line detection using suitable VHF sensors, 2. the methods to suppress disturbances and to distinguish between different types of discharges and 3. the interpretation of measured results to obtain knowledge about the insulation condition.