Analysis of distribution transformer insulation using domain method

The article discusses the state of transformer insulation. Return voltage measurement and the insulation resistance of windings were used to determine the state of transformer. While the measurement of insulation resistance is the basic method and is set in the standard, return voltage measurement is more complex method and in many cases is determine a clear result very difficult. For evaluation of results have mainly impact moisture content, content of conductive impurities in oil and degree of aging of paper insulation.