Abstract
Digital recorders have been used for impulse high voltage measurements in place of oscilloscopes and the accuracy requirements are specified in detail by the IEC Standard 1083-1: “Digital recorders for measurements in high voltage impulse tests”. Many factors such as sampling rate, non-linearities of amplitude and time base, internal noise level, interference and so on influence the accuracy . If the digital recorder is used in a reference measuring system proposed by the draft of IEC60-2, more accuracy is needed than the requirements specified by IEC1083. In this paper, authors dealt especially with the influence of the internal noise level of the digital recorder on the accuracy and clarified the relation between the accuracy and the internal noise level of the digital recorder for rrreasurements of standard lightning and switching impulse voltages. Furthermore, in order to eliminate the influence of the internal noise, the authors proposed the correction methods and showed that the methods remarkably increased the measuring accuracy for lightning and switching impulse voltage waveforms.
