Effect of soluble salt on conductivity of partial surface

Closely related to the flashover performance of insulators, the conductivity of partial surface is a new parameter to present the contamination without damaging the contamination on the surface of the insulators. This paper introduces a special probe, which is newly designed for measuring the conductivity of partial surface. Using this probe, we studied the effect of soluble salt component on the result of partial surface conductivity. We used NaCl and CaSO
₄
representing soluble salt and insoluble salt respectively to conduct artificial contamination experiments on the surface of hydrophilic glass. By changing the composition and content of soluble salt, we studied the equivalence relations of partial surface conductivity and Equivalent Salt Deposit Density (ESDD) under different conditions. The results showed that when the soluble salt is NaCl, the partial surface conductivity and ESDD have a quite good equivalence relation; when the soluble salt is CaSO
₄
, the partial surface conductivity is quite stable, unaffected by the change of ESDD, but when the soluble salts is the mixture of NaCl and CaSO
₄
, the ratio of partial surface conductivity and ESDD will change slightly with the change of the proportion of NaCl and CaSO
₄
. The experiment proved that partial surface conductivity is influenced more by soluble salt, which is in accordance with the situation when the insulator is flashovered because of contamination.