A versatile model for estimating breakdown voltage and its application for cryogenic gas mixtures

An improved model for the estimation of the breakdown voltages of gas mixtures is developed. The application and utility of the model is demonstrated by using it in estimating the breakdown voltages of gas mixtures containing helium and hydrogen that are being developed as an alternative cryogenic insulation and cooling media for certain high temperature superconducting (HTS) power devices. The concept of the developed model, which incorporates a generalization factor m, is presented. The first step of the model performs a nonlinear least square regression on the generalized formula of the pressure normalized ionization coefficient α/p for the parameter approximation. The second step introduces the parameter m that minimizes the root mean square error (RMSE) of the nonlinear least square regression to derive the versatile model. The validity of the model is demonstrated by comparing its estimated values with the results of the experimental breakdown measurements of several gas mixtures. Compared to the conventional breakdown voltage models, the new model showed improved agreement with the experimental results of the breakdown voltages.