Fundamental differences of the PD measurement according to IEC 60270 and in UHF range

PD measurements in the UHF frequency range are an important tool for diagnostic at GIS. A general correlation between the measurement according to IEC standard 60270 and measurements in the UHF range is not possible. By the use of a ldquosensitivity checkrdquo the quality of the UHF measuring system is verified at GIS. In this contribution the usual procedure is pointed out and the boundary conditions and simplifications are shown. The knowledge of this is important for the interpretation of the result of the sensitivity check.