Application of capacitive sensor for measuring water content in electro-insulating liquids

Abstract

The article discusses the problem of water content measurement in electro-insulating liquids using capacitive sensors. The article describes coefficients affecting reliability of the water content measurement. The authors discussed issues connected with water saturation limit in electro-insulating liquids. The authors also proposed a method which allows determining coefficients by means of which it is possible to calculate the water saturation limit in electro-insulating liquid as a function of temperature. Determining the coefficients allows proper calculating of the water content in ppm by weight by means of relative water saturation of the investigated liquid, what was measured with a capacitive probe. Propositions included in the article improve reliability of the method to determine water content in electro-insulating liquids and thus contribute to breakdown-free operation of electric power equipment insulated with these liquids.