Why the Smart Grid is More Than Just Smart Meters
“It means different things to different people,” says the manager of grid solutions at Toronto Hydro. “The term has become overused. It gets in the way.”
Many hydro customers in the city associate the term with the smart meters in their homes and the time-of-use pricing they enable. Some imagine a smart home or building equipped with intelligent appliances and lighting systems that interact with each other and can be remotely managed by software to reduce energy use.
Others think of a kind of energy Internet made up of millions of users and thousands of large and small power producers, all part of a complex web of two-way electricity flows.
The smart grid isn’t any one of those things – it’s all of them, and more. In fact, a big part of the smart grid that rarely gets discussed has to do with technologies that make our electricity system more reliable and safe. These are the behind-the-scenes technologies we don’t and aren’t meant to see. The better they work the less likely we are to notice them.
For the past three years Toronto Hydro has been giving some of these “smart” technologies a test run on the transformers and power lines that make up its electrical distribution network.
Take transformers, those large grey cans on hydro poles that convert high-voltage electricity down to the low voltage we use in our homes. The utility has roughly 60,000 of these devices spread throughout its operating territory.
“In the past we haven’t had any detailed information about how those transformers were performing – whether any were systematically overloaded or underloaded,” explains Ford, adding that even when the devices fail they don’t know about it until customers call to complain.
About 5,600 city transformers now have a kind of smart meter embedded inside, allowing the utility to know what kind of stresses are being placed on the device and to act proactively before its fails, which tends to be at the most inconvenient times – say, during a SuperBowl or hockey playoff game.
What benefit does this bring to electricity consumers? The typical transformer failure means affected customers will be without power for about 7.5 hours. On the other hand, a less inconvenient pre-planned outage aimed at upgrading the transformer before it fails only takes about 70 minutes.
This will become increasingly important as more homeowners add solar panels to their rooftops and plug-in electric vehicles overnight for charging. It will give the utility better insight into the changing patterns of electricity use in our neighbourhoods, and allow it to plan accordingly.
An added bonus: smart transformers make it easier to spot grow-ops that have illegally tapped into the system.
The utility is also monitoring some of its power lines. Sensor-based devices attached to the lines can spot abnormal electrical activity and alert control-room staff so they can analyse the data. The analytic software has become so sophisticated it can detect the signatures of different events, such as an overgrown tree rubbing up against a line or a jumping squirrel.
“We keep looking for more signatures of more events,” says Ford. “We want to identify potential faults before they turn into real faults.”
If, for example, a problem is identified as tree overgrowth, a crew can be dispatched to inspect and trim branches. The utility has seven power line monitoring devices installed to date, but plans to add more as part of normal grid upgrades.
On top of power line and transformer monitoring, Toronto Hydro is test driving feeder automation technology. Feeders are higher-voltage power lines that supply electricity to a large area of homes and businesses. Sometimes an unpredictable event, such as a vehicle accident or damage from a backhoe, can cause one section of a feeder to fail.
If a feeder serves thousands of people the resulting outage would affect all of them, and it could take 10s of minutes to a couple of hours for service to be phased back in. Automation technology can isolate a fault on a feeder line and almost immediately restore service to most of the customers affected.
Feeder automation technology has been installed on 10 of the city’s worst feeders since 2010. An outage on one of those feeders in August 2011 affected 4,493 customers. Normally all of them would have a long wait for the lights to come back on, but the automation technology isolated the fault to just one customer – the other 4,492 got service automatically restored within a minute.
It’s an extreme example, says Ford, but illustrates well how the technology can improve customer service.
“We’d like to see all of these technologies more widespread,” he adds. “The benefit is that customers will be interrupted less, and hopefully never even notice when they are.”
It’s not as sexy as the image of a smart home with an electric car in the driveway, solar panels on the roof, intelligent appliances in the kitchen, and a battery pack in the basement. That “stuff” will come, says Ford, but we need to lay the foundation first.
“What we’re doing today is making better use of our existing assets, getting more out of them by making them more effective and more efficient.”
By. Tyler Hamilton
Tyler Hamilton, author of Mad Like Tesla, writes weekly about green energy and clean technologies