Effects of Water Capillary Action on Capacitance of a Parallel Plate Capacitor

A condensation of water in circuit elements in humid air is common phenomenon. In this contribution we analyze the condensation of water between plates of parallel plate capacitor with an initial dielectric, the polyvinylchloride. We assume that inner walls of capacitor act like a flat capillary tube, as a distance between the capacitor plates is sufficiently small for occurrence of capillary action of water. The mathematical model of behavior of real water is given, which takes into account that a surface of water has a concave meniscus. The simulation of model in FEMM showed that there is a significant difference in the capacitance before and after the condensation. Furthermore, the water-air surface cannot be approximated as flat for higher voltages due to the voltage dependent water rise.