Evaluating Impulse Measurements-A New Aproach

Because the wide variety of generating and measuring systems for impulse voltages produces a large variety of impulse shapes to be measured, blanket requirements for measuring systems become much too stringent. Attempts to ease the requirements by assuming simple impulse shapes have resulted in Standards which are excessively severe for some conditions and insufficiently so for others. To over- come this, it is proposed that the maximum frequency which can be present in a system be estimated on the basis of the physical size of the system and that a specific characteristic of the measuring system´s step response be controlled to ensure that this frequency will be detected when present on a test object with a significant amplitude. The output oscillogram from any particular measurement is then used to establish which frequencies and perturbations are actually present on the test voltage and the appropriate characteristics of the step response are used to evaluate the accuracy with which they are measured. The ideas developed here are the basis for a proposed revisiton of an international standard for impulse measurements.