State of water in hydrocarbon liquids and its effect on conductivity [transformer oil]

The humidity or the dissolved water in insulating oils influences conduction and breakdown phenomena. The corrections between the amount of dissolved water and the electrical properties have been investigated. However, the effect of water has been based only on the total amount of water because in the past there was no way to observe the state of water in oil in an electrical field. With the availability of Fourier transform infrared (FTIR) spectroscopy to characterize water clusters, the effect of water in transformer oil can be reassessed based not only on the amount of water, but also on the state of water. In this paper, IR spectra of water in several liquid hydrocarbons and conduction current were measured at the same time. The selection of the liquid hydrocarbons was made on the basis of the degree of polarizability of the liquids. Because the water molecules combine with the polar structures by hydrogen bonding, the state of water depends on the polarizability of the oil. As a result, there is a difference in conduction phenomena depending on whether water is free or combined with the polar structure of the liquid