Dielectric fluids in motion

The behavior of transformer oil and other dielectric fluids used for the cooling and insulation of power system equipment is significantly influenced by motion enforced by the action of circulating pumps. Two important factors impact the situation. First, charges generated by streaming electrification in critical parts of the hydraulic circuit having high velocity and/or turbulence can accumulate to distort the electric field in positions where dielectric integrity is prejudiced. However, the dielectric strength of the fluid is also altered per se by the actions of the flow in a complex, but predictable, manner. Both of these aspects need to be understood to permit informed design, operation and monitoring of forced-cooled equipment.<>