Investigation on Carbon particle formation with Electro-Thermal ageing of Transformer oil

Present work deals with accelerated electrical and thermal stress on transformer oil and its characteristic variation on Fuller’s earth (FE) reclamation. The influence of carbon particles in the fluid, its role on thermal ageing characteristics can be understood by electrical characterization. Reclamation of insulation fluid extends the lifetime and reliability of the transformer over the year of operation. The average particle size of carbon particles on electrical breakdown are in the range of 644 nm. Dielectric response spectroscopy (DRS) which identifies the conductivity and relative permittivity variation with the effect multi-stress ageing. Conduction mechanism with higher electric field is simulated by current-voltage (IV) characteristics using non-uniform field configuration to derive the ionic mobility of the liquid. Dissolved decayed products and turbidity showed drastic enhancement with multi-stress ageing than the thermally aged specimen. Reclamation with fuller earth treatment removes the carbon traces and ageing by-products in the fluid regaining its relative dielectric performances. Rheological aspects with viscosity indicates the ageing by-products build and also its characteristic variation on the reclamation process.