Transient Measurement Techniques in EHV Systems

Two different measuring techniques have been developed in order to reduce the measurement errors observed during recording of transients in EHV systems, caused by interference due to ground potential differences. The first one is based on the application of an opto-electronic link between the HV measuring apparatus and the remotely located multi- channel recorder. The second, more conventional technique utilizes a large copper band llaced in parallel with the measuring cable shield. An optimum geometry for the band and the cable was determined from a model study. Results of application of these two measuring techniques in EHV system tests are presented.