Experimental and mathematical modeling of the effect of non-soluble and low soluble salts and salts mixture pollution on dc flashover of high voltage insulators

This paper is aimed at the experimental study of the influence of non-soluble and low soluble salts and mixtures of salts on dc critical flashover voltage. The influence of the type of pollution on discharge parameters n and N, and their implication on the values of dc critical flashover voltage for both polarities is also analysed and discussed. A mathematical model enabling to compute the critical flashover voltage (U_cri) is proposed. It is shown that the calculated U_cri are in accordance with the experimental ones. It also appears from this study that: (i) the most important components of the discharge column are water vapour and air; and (ii) the transfer of metallic ions has not a significant influence on U_cri.