Power transformers play an integral role in the operation of today's electric power grid. Failures carry not only the risk of extended downtime, but also significantly impact a company's finances and reputation. In today's climate, these risks are more pressing than ever, with a number of influential factors peaking at the same time. Understanding what the current risks are, and how to mitigate them, is crucial in maintaining the smooth operation of power transformers, protecting your fiscal position and safeguarding your reputation.
Foremost among these risks is the rising demand for electric power together with an aging infrastructure. While environmental drivers for energy efficiency have helped stabilize overall power demands at a more constant level, electricity is making up a growing proportion of global energy consumption.
According to the US Energy Information Administration, the proportion of energy delivered in the form of electricity in the US has risen "significantly" in the past six decades. In 1950, it stood at four percent; in 2010, 29 percent. These figures demonstrate not only that the modern world consumes more electricity, but it’s also becoming more reliant on it for day to day living.
Transformer failures, therefore, have greater potential to be disruptive than ever before. The fact that this increased reliance is placed on the shoulders of transformers already operating outside of their extended lifetime is one of the key challenges facing the industry today – the average age of substation transformers is now 42 years; their designed lifespan is 40 years.
Compounding concern is the fact that investment in new transformers is not currently keeping up with demand. In developed countries, the 1950s, 60s and 70s saw significant investment in power transformer infrastructure. This then dropped off in the 80s, 90s and 2000s. In the US, for example, investment peaked in 1974 and reached a low in 1996 [Source: EIA; SPX Electrical Products Group, May 2010]. This dearth of investment in recent decades, not just in the US but across the world, is a major contributing factor to driving up the average age of transformers.
Globally, the rate of failures of power transformers is typically 0.3 percent per year, which statistically equates to six transformers in a fleet of 2,000. Which transformers will develop faults and which will eventually fail is impossible to predict without condition based assessment every transformer.
This brings us to another pertinent factor as to why transformer maintenance and monitoring is such a topical issue. Technological advancements have brought us to the next era in transformer upkeep - online monitoring. Representing a significant leap forward in what is possible in terms of measurement, online monitoring for the first time enables real-time feedback on the condition of transformers. This allows us to spot developing faults as they appear, discern trends that may indicate declining performance and, crucially, provides the power to prevent failures.
Through online monitoring, it's possible to access more data on transformers than ever before - all in real time. Enabling companies to track moisture, temperature and dissolved gas levels, online monitoring devices eliminate the risk of improper oil sampling.
Identifying trends and a thorough knowledge of transformer conditions are essential in deploying effective annual condition-based maintenance plans. Accurate, real-time data provides the most up-to-date picture of which transformers need immediate attention and the potential consequences of inaction. The result is a sound basis for making the most cost-effective maintenance decisions.
The next blog post will discuss the benefits of online monitoring in more detail. Stay tuned!