Surface Hydrophobicity in Medium Voltage Terminations


  • Kenneth Kimmo Miika Väkeväinen Ensto Finland Oy



The surface hydrophobicity in medium voltage terminations is studied in this paper to see if the performance of aged heat shrink terminations could be improved. Terminations which are used inside of unheated outdoor enclosures can often be subjected to leakage currents and surface discharges along the insulating surface if the environmental conditions inside the enclosure become harsh. The discharge phenomena on the insulating surface is generally not critical but continuous electrical activity on the surface could eventually lead to a flashover or breakdown as the materials age. The effect of surface hydrophobicity was studied by comparing the performance of heat shrink terminations over a longer time in operation. Improvements were done to aged heat shrink indoor terminations which already had signs of discharge occurrence on the termination surfaces. The results indicate that the performance of these aged terminations improved simply by increasing the surface hydrophobicity of the original installation. The improvement can be done by applying a silicone coating on the termination surface. This solution offers a convenient method for improving the performance of aged heat shrink terminations used in unheated outdoor enclosures.


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