Refurbish not replace
UK steelworks have gone through a turbulent time in recent years, but there is now some stability as the UK and global marketplaces once again appears more attractive. Although investment is being made, money has to be spent wisely, and transformer refurbishment, with a focus on the health of the insulation system (oil and paper), has become a priority for Tata Steel Port Talbot’s engineers who look after the high voltage feed to this 2,000 acre site in South Wales.
With pressure to reduce the carbon footprint of all maintenance and replacement activities, the need to deliver good value and the sheer good sense of not replacing transformers just because they are “getting old” makes refurbishment a technical and economically viable option. Tata Steel, one of the largest steel producers in Europe, engaged Electrical Oil Services (EOS) at an early stage to discuss options for treating the insulation system as part of their transformer refurbishment programme. EOS is the leading supplier of unused and reclaimed electrical insulating oils and associated services throughout the UK and parts of Europe, and a strong brand of HCS Group.
Health screening: assessing the transformer population
With 17 supply transformers, each of them 66 kV and many of them feeding critical parts of the steelworks, a wholesale replacement programme was never a viable option for Tata Steel. Instead, each transformer was sampled with the support of EOS engineers. In addition, a Transformer Condition Assessment (TCA) analysis was carried out by the leading UK laboratory TJ|H2b Analytical Services Limited. This in-depth analysis gave EOS engineers and Glen Evans, Tata Steel’s Area Engineering Manager for High Voltage Systems, a comprehensive baseline assessment of the current oil condition and, more critically, the state of the paper insulation.
The baseline information on the 17 supply transformers, together with the critical assessment of the physical state of each transformer, was the prerequisite for Tata Steel to put together a risk-based refurbishment plan focusing on the most critical transformers for steel production at Port Talbot.