Estimation of the Water Content in High Voltage Oil-impregnated Transformer Insulation

This paper describes the possibility methods of estimation water content in oil impregnated cellulose insulation of HV transformer. The first method is based on measured or calculated relative humidity of transformer´s oil. This method is usable for energizing transformers. The second method is based on measured dielectric dissipation factor and capacitance of insulation zones of transformer and dielectric parameters of oil. This method is usable for no-energizing transformers.