The Growing Problem of Momentary Power Outages: What Can Utilities Do?

S&C Electric’s US President Michael Edmonds talks about a problem not caught by old-school reliability measures — momentary power outages that disrupt sensitive equipment. The problem is growing, he says. The cause may surprise you.

momentary power outages

Michael Edmonds, S&C Electric’s US president

Utilities for years have worked hard to improve their performance, and they have some stories of success in reducing the number and duration of sustained outages. What’s also happening is that the very strategies utilities have developed, including testing the lines to identify and isolate sustained outages, have created another problem: a rise in momentary outages for customers along the unaffected lines included in those tests.

As a result, complaints are up stemming from the impact these “blinks” on the lines have on customers’ sensitive powered devices. Perhaps not surprisingly, some utilities are being caught off guard by this growing customer concern.

One of my colleagues, for example, mentioned that during a recent meeting, a hospital facilities manager stood up and said his facility had 40 momentaries in a single day. Those momentaries were short enough to not trip on the backup generator, but imagine a respiratory machine that stops working for 30 seconds. For him, this rise in momentaries is a very big issue.

Literally, the next person to stand up at the meeting was a representative from the hospital’s utility who was a bit upset at being called out. His utility’s story is that, with its smart grid initiative, performance has improved. But that’s because the utility measures only sustained outages, so from its perspective reliability has gotten better. It’s just not looking at the bigger picture.

Utilities’ investment in strategies to combat sustained outages also are being called out. A utility in Wales, United Kingdom, for example, mentioned to a local manufacturer that it was spending $25 million to improve power supply to the plant. But what the utility did was install traditional reclosers, which resulted in the manufacturer moving from an average of one outage per year to seven or eight. So the customer was like, ‘you just told me you spent something like $25 million to improve the supply, but it’s gotten worse. What’s going on?’ The utility response was, ‘I don’t know what you’re talking about. There’s nothing wrong with what we’ve done.’ But what they’ve done is introduce more momentaries.

momentary power outagesAnd as utility power systems change by having more solar photovoltaic panels (PV) on customer rooftops, what happens when a “blink” knocks out that PV system for five minutes? This represents more ways blinks will be noticed, and customer satisfaction will go down.

What these stories illustrate is the inconvenient truth that momentaries are a growing issue. Utilities, however, don’t even measure them. And utility regulators haven’t been pressing them to do so because this system issue has not been well measured.

So the secret in the room is the 1960s way of measuring reliability has addressed only sustained outages, not momentaries. We can do better in protecting our customers from these annoying and potentially very expensive disruptions, so no outage is left behind.

I’d be interested in hearing about your utility’s strategy for reacting to the rise in momentary outages. In a future blog item, I’m going to discuss how social media is playing a growing role in motivating utilities to address the problem.

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