Sensitivity & errors in transient voltage measurement of gaseous ionization

Abstract

The relatively new transient voltage method is a promising technique for measuring the discharge parameters, particularly ionization coefficients, in gaseous dielectrics. A comprehensive theory for the method, including the effects of electron longitudinal diffusion, has recently been developed. The first results from the method, using that new theory, have also been obtained. The aim of this paper is to present a sensitivity and error analysis of those results. That analysis is of particular interest because of the non-analytic nature of the governing equations. Sensitivity curves are presented for each independent variable over the full range of applied field (400 < E/N < 2200 Td, 1Td= 10−17 V.cm2). Results are also presented for the weighted error contribution of each variable to the overall variance as well as the overall coefficient of variation in primary ionization coefficient as E/N varies. The results are discussed in relation to the competitiveness of the method, the role of longitudinal diffusion and the future use of automatic measuring systems able to exploit the single shot nature of the discharge measurement technique.