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When Should You Replace Your Transformer?

For decades, the conventional wisdom in the energy industry was that transformers have lifespans of between 30 and 50 years, and for many businesses they are an aspect of their energy infrastructure that they simply purchase and forget about. However, aging transformers can represent a significant risk to a business, both in terms of wasted energy and subsequent costs and as a potential point of failure. 

The issues around aging transformers is UK-wide, with more than 70% of electrical transformers in the UK having been in operation for 25 years or more. Increasing numbers are exceeding their design life, and as a result services including transformer maintenance and refurbishment have steadily become more frequently used. In many cases, the transformers on a site will predate the career of any staff, and there can sometimes be relatively little oversight of their age and condition. 

Transformers represent a major investment, and many businesses with other cost concerns relating to energy are opting to extend the lives of their existing transformers as much as possible rather than investing in a replacement. It could be a recipe for disaster, as if a transformer suddenly fails and cannot be repaired, a site could face a lengthy period of downtime and disruption while they await a replacement. 

Signs that a Transformer Needs Replacing 

There can be a number of signs that your transformer may need replacing, aside from age. Firstly, it is important to establish the age and condition of the transformers you have. Older transformers invariably have higher losses, and could be adding substantially to your energy costs, carbon emissions and consumption. A site survey can help to identify transformers that are aging and experiencing high levels of losses, or that are presenting a risk of failing and compromising energy resilience. More obvious symptoms can include a noisy or vibrating transformer, which can be indicative of an issue. 

How Much Could a New Transformer Save? 

Transformer technology has improved significantly over the years. One advantage of replacing a particularly old transformer is that its replacement is likely to deliver a substantial improvement in energy efficiency, which can significantly reduce the energy costs and related carbon emissions of a site. A typical efficiency rating for an aging transformer may be around 85%, although it may be even lower. In comparison, modern, low-loss transformers generally have energy efficiency as high as 99.75%. 

Amorphous core transformers present a significant improvement compared to older styles of transformer cores. Still relatively new to the market, amorphous cores can eliminate up to 80% of the losses experienced by conventional transformers. While typically a higher upfront cost, amorphous core transformers will cost only around 1% of their initial purchase price per year in additional energy costs. In contrast, the losses associated with older transformers can translate to additional energy costs equivalent to the entire purchase cost of the transformer itself every nine months.