Standardizing the interpretation of on-line VHF PD measurements on turbo generators

Abstract

Presently, an expert is needed to interpret the results of an on-line VHF PD measurement on a turbogenerator. And even then, different experts will interpret the results differently. Standardization of the interpretation of online VHF PD measurements is needed before a generator operator can use online VHF PD measurements in his or her maintenance program. This paper presents such a method for interpreting the results of on-line VHF PD measurements performed on turbogenerators. Using the interpretation method, the stator insulation system is classified into one of the following categories: "insulation system ok", "insulation system ok?", "insulation system not ok?" or "insulation system not ok". discharges. The presented method is currently used for the interpretation of on-line VHF PD measurements on turbogenerators throughout the Netherlands.