The influence of electrohydrodynamic motion on the breakdown of dielectric liquids

Abstract

A mathematical model for the transient electrohydrodynamic (EHD) motion in liquid dielectrics is used to examine the behaviour of dielectric fluids flowing at various velocities between high-voltage electrodes. The resulting flow patterns and space charge distribution profiles are correlated with observed variations in transformer-oil breakdown properties, and explanations for these variations are proposed.

A study of correlation between the ect and ehd properties of different aged insulating oil mixtures that can Be an alternative to mineral oil for the insulation and cooling of power transformers

“…According to Fleszynski et al, in addition to the phenomenon of static electrification, the electro-hydrodynamic phenomenon that occurs inside the transformer can also play a very important role in the breakdown of these energy devices [ 5 ]. Several researchers such as Theodosius et al have shown that the electro-hydrodynamic phenomenon can play two roles, one positive and the other negative [ 6 ]. The positive role of electro-convection is related to the effective electro-hydrodynamic discharge of charges, leading to a reduction in local charge densities and electric field strength.…”

“…The positive role of electro-convection is related to the effective electro-hydrodynamic discharge of charges, leading to a reduction in local charge densities and electric field strength. Intensive electro-convection flows - in their negative role -lead to the development of cavitation processes, initiating electric discharges in the oil [ [6] , [7] , [8] ]. Today, these phenomena of static electrification and electro-convection of insulating oils therefore concern several researchers around the world [ 5 , 16 , 17 ].…”

Effect of co-field flow velocity, temperature and dissolved gases on the direct breakdown voltage of transformer oil using point-to-plane electrodes

“…Limited work in flus area was confined to cross-field motion [3,4]. 'The present paper gives results on the effect of temperatie on the breakdown voltage of degassed and 02-saturated transformer oil under enforced co-field flow, and is an eiiension of previous work reported by the present authors [5-71.…”