Flow electrification in transformer oil/cellulosic systems

Liquids are commonly used in power apparatus to both transfer heat and withstand high electric stress. The combination of charge separation at interfaces between the moving oil and boundaries and forced convection can give rise to the generation of electric fields. Either alone, or in consort with the fields imposed by energization of the equipment, these can contribute to insulation failure. Examples include freon cooled static power conditioning equipment and oil cooled transformers. Both to ensure reliable operation of existing equipment and to guide in the development of the next generation of power apparatus, it is desirable that flow electrification be reduced to an engineering science.