Very fast high voltage impulse generator

Abstract

Some high voltage applications use very fast impulses with rise time less than 100 nanoseconds. Measurements of these impulses are difficult, and a lot of different voltage dividers are used. In many cases, inadequate metrological support of calibrations of these dividers is a problem. In recent years, an etalon for very fast high voltage impulses is missing in the Czech Republic. The future aim of our work is the realization of such a reference divider. However, in the first step, it is necessary to develop suitable very fast high voltage generator, which is the subject of this paper. Realization of a stable very fast high voltage impulse generator with light and relatively low cost construction, and with rise time less than 100 nanosecond, at a voltage level of the order of 100 kV, into a capacitive load representing e.g. tested insulator, is not possible with design of common commercial impulse generators. An important part of the paper is a design of electrical circuit of the very fast impulse generator with a numerical simulation which has done limit parameters of all components of the device. Finally, the impulse generator for voltage up to 100 kilovolts and a rise time less than 50 nanoseconds has been realized. The results of verification measurements in case of two different types of voltage dividers are presented in this paper.