Neglected transformers 

The customer has around 20, 66kV transformers that are critical to the continual production of steel. These transformers had been neglected for 15 years and now, with new owners and a vision to continue production for at least the next 5 years some investment was needed to ensure these transformers were in the best possible health.

EOS held a series of site meetings to jointly review (with the customer) the condition of the oil in each transformer, where necessary EOS took additional samples and carried out detailed TCA (transformer condition assessment) analysis to determine the strength of the paper insulation. Once a baseline assessment of the oil and paper was determined and the regeneration process fully explained, in particular the benefits compared to straight oil replacement, a plan was developed to treat two transformers a year prioritising the worse cases .

2 years after on site regeneration acid levels, DDF, IFT and water content remain below BS148:2009 with water reductions in paper estimated to be around 15 – 20%