For both utilities and industrial facilities, substations are keystone assets. When there’s an issue at a substation, the resulting problems can be widespread and significant. In the quest for greater reliability and more efficient operations, traditional approaches to maintenance are increasingly falling by the wayside as substation owners join the revolution and adopt more predictive maintenance approaches. The demand for improved system reliability is also significantly increasing.
The maintenance revolution has been underway in industry for many years. Both process and manufacturing facility operators have embraced the seismic shift from traditional maintenance practices to a very different and far more effective approach. Today the revolution has grown to include utilities and other organizations engaged in power generation, transmission and/or distribution.
The revolution is the movement from cycle, time, or usage based maintenance to a predictive maintenance approach grounded in actual need rather than arbitrary schedules. The revolution is being propelled by the ever-increasing number of more intelligent devices that self-monitor critical asset health attributes and automatically report that in-formation to facility operators.
These smarter devices – with the ability to “see, hear, and feel” – provide information that, combined with test and inspection data, enable substa-tion owners to implement a far more efficient and effective maintenance strategy, with greatly in-creased asset reliability. The ISO 55000 asset management standard underscores the criticality of understanding asset condition and risk of failure, classifying the availability of that knowledge as a best practice.
Respondents to a recent global survey of 220 utilities put asset management ahead of other business efforts, with 52% saying it is a high priority. In the same survey, 55% of respondents said concerns about asset management are more important today than 12 months ago. Maintaining asset health through appropriate maintenance is central to an effective asset management strategy.
Triggers for maintenance activity
Car manufacturers long recommended oil changes every 5,000 miles and tire rotations every six months, with fine print that the interval be short-ened based on harsh use or conditions. But it’s intuitive that this arbitrary maintenance schedule made little sense. Whether your car was driven gen-tly in a mild climate or saw harsh duty in severe weather, the maintenance advice was the same. Many, probably most, consumers wasted money on unneeded service; others neglected service that would have extended vehicle reliability and life.
It might seem logical to adjust maintenance schedules based on the age of the equipment. When looking at substation high voltage breakers and transformers, for example, surely older assets are more prone to failure and therefore require additional attention. Surprisingly, not so.
The Hartford Steam Boiler company provides equipment breakdown insurance for a variety of devices, including transformers. In their actuarial calculations related to transformers, they studied 94 insured failures to identify risk factors. Their study concluded that asset age is a poor indicator of potential failure. Other factors provide far more reliable indications of pending problems.
“We performed the same kinds of analysis but studied over 10,000 transformers,” says Craig Stiegemeier, Director of Technology, Transformer Remanufacturing & Engineering Services North America for ABB. “We found exactly the same thing; age alone is not a good indicator for pending trans-former issues or failure.”
If duration of use and age of equipment are poor triggers for maintenance activities, surely cycles or rotations are better indicators. Again, not necessarily. The type and design of the asset, its maintenance history, operating environment, and other factors may each provide a better trigger. But, as will be pointed out, the most reliable trigger for maintenance action requires consideration of multiple factors.
Drivers for more effective maintenance
The increasing urgency to find more efficient and effective approaches to maintenance is the result of several long-term trends.
- Aging infrastructure: Many assets related to power distribution are very long in the tooth. A 2015 report found that 70% of transformers are 25 years or older and 60% of circuit breakers are more than 30 years old.
- Aging workforce: The engineers and technicians responsible for maintaining those assets are also aging. Over half of the current utility workforce will be eligible to retire in the next six to eight years, and 72 percent of energy employers are having difficulty finding quality replacements.
- Flat operations & maintenance spending: De-spite an increased need for maintenance, 57% of utility companies plan decreased or flat O&M spending.