TABLE OF CONTENTS E. Gockenbach
The measurements of voltage and current in high voltage tests are difficult because the amplitudes are high and they cannot be measured directly with conventional measuring and recording systems. Furthermore, not only the peak value but also the shape of the signal, particularly for impulse voltage and current, should be measured and evaluated, and this requires an adequate recording system using either an oscilloscope or a digital recorder.
A high voltage or high current measuring system consists generally of a converting device, a transmission device and a recording device. An optimised measuring system has components which fulfil the required performance and are similar in their characteristics. The measuring system is as good as the weakest part of the system, and therefore it is not necessary to require an exceptional performance from any one of the components.
The converting device should reduce the amplitude of the signal to be measured to a value which is suitable for the transmission and recording device. The output signal of the converting device should be an exact replica of the input signal concerning the wave shape and the time parameters. This requirement is very strong in many cases and therefore the measurement error should be estimated and evaluated carefully.
In the measuring systems the converting device is usually the critical component due to its physical size and transfer behaviour. A simple and typical test to check the transfer behaviour is the measurement of the unit step response. Assuming...
