Digital monitoring and analytics provide unprecedented visibility over the condition of equipment, helping businesses improve reliability and extend lifespans.
From power generation to transport and manufacturing, transformers are crucial components of electrical networks – stepping voltage up or down to ensure the safe and efficient distribution of power.
When transformers work as intended, it’s easy to take them for granted. But problems are more common than you might think: every year, one in every 200 experiences a major failure (Source: CIGRE TB 642, 2015).And when this happens, there’s a big impact. The fire that shut down London’s Heathrow Airport this year – which we now know was due to moisture in a bushing, leading to a short circuit and arcing in the transformer – is a particularly high-profileexample. But it’s by no means the only one. The following month, for instance, a transformer set alight at another substation in West London. And a transformer failure in California last year led to outages in multiple cities, leaving more than 30,000 people without power.
Events such as these not only present a major safety risk to staff and customers. They also create substantial costs. Businesses need to shut down operations to address the problems, losing productivity through unplanned downtime. In addition, they face considerable repair and replacement expenses. New transformers are a big investment – and getting hold of them is becoming increasingly difficult. Global transformer supply lead times have risen from about 50 weeks in 2021 to an average of 120 weeks in 2024 (Source: Woods Mackenzie, 2024). And in the US, prices rose 80% between 2020 and 2024 (Source: St. Louis Federal Reserve Bank Transformer Price Index, 2024).
These issues, combined with rising demand, are putting growing pressure on electrical asset managers across a range of industries. To meet their goals in tough market conditions, businesses must extend the capacity and lifetime of their equipment as far as possible. But this in turn can increase risks, because the likelihood of a failure increases as aging transformers face higher loads. The fundamental question facing organizations is how to maximize the value they get from the devices while avoiding dangerous, costly and disruptive incidents. The current shortage of workforce skills needed to operate and maintain transformers only intensifies the challenge. So, what’s the answer?
The difficulty of seeing inside a transformer
These challenges have their roots in the nature of transformers and the problems that affect them. One of the most common causes of fires in the devices is the breakdown of internal insulation. At the start of a transformer’s life, it includes paper insulation consisting of long intertwined cellulose chains – forming a durable structure that can withstand mechanical and electrical stresses. But as it ages, this paper loses strength, making it harder for the equipment to handle these events and potentially leading to failure.
The speed at which this process takes place isn’t uniform. It’s significantly affected by temperature and moisture levels – so monitoring these is critical to understand the condition of a transformer’s insulation, and in this way assess its level of risk. But this is where difficulties arise, particularly with measuring moisture. The only way to do this accurately is to shut down the system and remove the transformer from service. But clearly, that’s not feasible to do on a frequent basis.
For this reason, engineers have developed various approaches to estimate the water content in a transformer’s paper insulation. Typically, this involves calculations that rely on measuring the level of water in the device’s oil through a lab analysis of a dissolved gas sample. But the connection between water content in oil (WCO) and water content in paper (WCP) is by no means straightforward. It depends on a number of different factors – such as temperature, pressure, the type of oil and the type of paper. And it’s a dynamic relationship that’s constantly changing based on these variables and others.
So in an operating transformer, where loads and ambient temperatures are never static, determining the level of moisture in paper insulation is extremely complicated. A dissolved gas analysis (DGA) at a single point in time will only ever provide a partial answer. And repeatedly carrying out this process quickly becomes expensive. What businesses really need is an ongoing view of the critical metrics, and an in-depth understanding of how these relate to risk.
Enhancing reliability and extending lifespans
Our Transformer Monitoring Solutions now deliver this through an innovative, cost-effective approach based on digital monitoring and AI-powered analytics. It uses a single, IoT-connected probe that can easily be installed on a transformer to measure levels of temperature, moisture, and vibration, as well as partial discharge signals, inside the device. The software then uses this information, combined with further data from external sensors, to provide an accurate, constantly updated picture of the conditions inside. Because this process is continuous, it smooths out variations arising from the dynamic conditions within the transformer to provide reliable assessments of its internal state and the associated risks.
These insightsare presented in a user-friendly digital dashboard that offersunprecedented visibility over the status of the device – including detailed operational data as well as an at-a-glance health index, maintenance recommendations and lifespan forecasts. This empowers businesses to manage their transformers much more effectively, maximizing value and minimizing risk. System operators can spot early signs of potential problems and take action to tackle these before they create disruptions. And they can make data-driven decisions about when to maintain and replace equipment – extending asset lifetimes while enhancing reliability.
How Photosol avoided the costs of unnecessary replacement
The benefits of this approach can clearly be seen in Schneider Electric’s recent work with Photosol – an independent photovoltaic energy producer in France, whose subsidiary Photom leads the engineering, management and maintenance of its electricity production plants.
It’s critical for the company to avoid transformer outages, which would prevent it from injecting power into the grid. An initial dielectric analysis had suggested that four of its transformers needed replacing. But by using our Transformer Monitoring Solutions (EcoCare & EcoStruxure Transformer Expert) for condition-based maintenance, Photosol discovered that only one transformer was actually at risk. This meant the business could save a substantial amount (Almost 500,000 US Dollars) by avoiding the unnecessary replacement of three transformers.
Watch the video: How Photosol ensures peak transformer performance
A smarter approach to transformer management
We’ve discussed in a previous post how transformer monitoring helps businesses avoid failures, extend asset lifespans, and reduce OpEx. Photosol’s experience makes clear exactly how our transformer monitoring solutions give customers the information they need to optimize the performance of their transformers. Their comprehensive analytics allow electrical asset managers to detect more than twice as many faults as they can with offline DGA (30% compared to 72%; Source: IEEE C57.143). With this enhanced understanding, businesses can potentially keep the devices in operation for ten, or even 20, further years than they would otherwise have done. This leads to substantial savings – particularly when multiplied across a fleet – that far outweigh the costs of digital monitoring.
And since our service is easy to install and connect, there’s no reason to wait. Get in touch now to begin a more proactive, informed approach to managing your transformers. Discover more about how digital monitoring can support better transformer health and performance at our Transformer Monitoring Solutions web page.
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