Determination of Moisture Content of Insulating Oils by CoCl2

Vladimir Kozlov,Alexander Turanov,Olga Kurakina,Olga Turanova

doi:10.52254/1857-0070.2021.1-49.07

Abstract

Moisture content is one of the parameters of transformer oil that determine its quality. This parameter is one of the most critical, which is closely monitored. During the operation of transformer oil in the power equipment of electric power systems, about 10 grams of water per ton of oil is allowed, i.e. the permissible proportion of water is 10 ppm (ppm). The aim of the work is to develop a new method for determining the permissible proportion of water in transformer oil in small quantities. This goal is achieved by performing spectral studies of transformer oil samples in the UV and visible range with the addition of cobalt (II) chloride (CoCl2) powder. Сobalt (II) chloride has the ability to change its color depending on the amount of water of crystallization. The most significant result of the article is the conclusion, obtained on the basis of the recorded spectra, about the relationship between the optical density of the spectrum in the range of 360-490 nm and the moisture content of transformer oil when adding cobalt chloride powder. The significance of the results obtained is that the authors have proposed a new optical method for determining small values of the proportion of water in transformer oils, based on the dependence of the optical properties of cobalt (II) chloride on moisture content.This method has a very high sensitivity, low cost for determining the proportion of water and is very promising for solving problems of power energy.

Highlights

Transformer oil is a highly purifed product of oil refining, an electrical insulating material, an arc-extinguishing and heat-removing medium, as well as an environment that protects the solid insulation of the transformer from moisture and air penetration
This paper demonstrates the effective application of CoCl2 for the determination of W of transformer oils by optical spectrophotometry in the visible and UV spectral region
An abrupt change in optical density (D) near 400 nm arises due to the absorption and dispersion of radiation by colloidal and solid particles which are present in transformer oil

Summary

Introduction

Transformer oil is a highly purifed product of oil refining, an electrical insulating material, an arc-extinguishing and heat-removing medium, as well as an environment that protects the solid insulation of the transformer (cardboard) from moisture and air penetration. It possesses excellent antioxidant properties, which makes it possible to maintain long-term operation of electric power equipment. During the operation of transformers, the oils filled in them undergo profound changes, which are usually characterized by the concept of "deterioration", including changes in its chemical and electrophysical properties. Deterioration of transformer oil causes oxidative processes. The oxidation process is influenced by such a characteristic as the moisture content of the oil [1]

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