Fundamental Interpretation of the Salt Effects on Limiting Flashover Voltages of the Salt-Contaminated SiO2 Plates in Terms of Solid-State Electrochemistry

The interpretation of the limiting flashover voltages (LFOV) observed on SiO2 insulator plates contaminated by nine common salts (NaCl, NaNO3, Na2SO4, MgCl2, Mg(NO3)2, MgSO4, CaCI2, Ca(NO3)2 and CaSO4) has been carried out in terms of the concepts of solid-state electrochemistry. On the basis of the hypothesis that the salt under the active electrode is dry during flashover, it has been shown that the LFOV values for various salts are roughly related to their heats of formation per equivalent and bandgap values. The alternative hypothesis that the salt under the active electrode is wet has also been examined and the possibility of interpreting the salt effects on LFOV values in the context of this hypothesis has been explored.