Introduction: This project is to use the recently commissioned ENWL portable oil regeneration unit, based at our Central Oil Reprocessing Depot (CORD) in Blackburn, Lancashire to undertake oil regeneration on a sample primary transformer within the ENWL estate with the aim of deferring replacement of the identified unit beyond at least financial year 2017/18.

The oil regeneration process consists of connecting the regeneration unit into the oil circuit of the transformer and then pumping the oil through various sieves, filters and heaters to remove impurities and dry the oil. In order to ensure this is economically viable it is essential to properly understand the effect of the regeneration on the transformer oil condition and the subsequent rates of deterioration following the proposed intervention which is made more difficult due to the loss of historical oil data held in the untreated oil

Objectives: Following the DPCR5 settlement it is now necessary to investigate alternative transformer management options that have previously not been considered and the technique that would appear to offer the greatest opportunity to improve the transformer Health Index (HI) and thereby extend the operational life is transformer oil regeneration. The aim is to test the efficacy of oil-regeneration as a reliable asset management technique. In addition Manchester University have been recruited to analyse the performance of the oil regeneration.