抄録
The water dissolution into the insulating oils deteriorates the insulating performance of the oils. Although we are paid attention to dissolving of the water into the oils, the situation or state of water has not been well investigated. Then the effect of water on the electrical properties had been discussed by the total amount of water without confirming the transportation of the water state under the electrical field.
In recent years, the relation between IR spectrum of a water molecule in liquid materials and its state has been studied, then it has become possible to observe directly not only the state of the water in the oils but also the transportation of the water state under the electrical field. In this paper, we measured the IR spectra of water in Di-Octhyle-Phtharate (DOP) before and after the electrical field was applied. As a result, the water behaved as a water cluster bound by DOP molecules. Over the 90% water clusters behaved as a water dimer, and the other was a water trimer or polymer. As comparing both of the IR spectra measured before and after the electrical field was applied, such the state of the water does not change under the electrical filed (20-100[kV/cm]). It means that the conduction current or tan δ can be determined by the content of the bound water clusters without considering the transportation of the water state.
