Research on Reliability and Lifetime of Solid Insulation Structures in Pulsed Power Systems

Abstract

Based on the Weibull statistical distribution and the thickness effect on dielectric breakdown strength <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</sub> , a formula to evaluate the reliability of solid insulation structures (SISs) in pulsed power systems is derived. By calculating this formula, it is concluded that an increase of 1.4 times in the dielectric thickness <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> or a 3/4 decrease in the applied voltage <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">U</i> will increase the reliability of SISs by “9.” Moreover, by introducing the variable of pulse number <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> into the Weibull statistical distribution, a formula to evaluate the lifetime of SISs is also derived. It is concluded that when the time shape parameter <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</i> is equal to 1, an SIS is in its normal lifetime stage, and the lifetime can be described by the Martin's formula; when <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</i> is not equal to 1, the Martin's formula should be revised. To verify the lifetime formula, experiments were designed and conducted. In the end, useful suggestions on design of SISs are summarized.