Influence of the test voltage function over lightning impulse response parameters measured by long cable

The test voltage function or k-factor was newly introduced in IEC 60060-1:2010. With the k-factor combined with base curve technique, lightning impulse parameters have been evaluated much easily and stably than with the old method defined in IEC 60060-1:1989. Now there has been a report in IEC TC 42 committee that front time evaluated from recorded curve of a smooth waveform at the end of a long measuring cable becomes much larger by IEC 60060-1:2010 definition than with IEC 60060-1:1989 description. Authors could not only confirm this phenomenon and found reasons to cause but also propose a technique to circumvent this difficulty. In the paper, details of the counter measures and arrangement of the measuring system, which eliminates erroneous front time evaluation, are introduced. © 2018 The Institute of Electrical Engineers of Japan.