As temperatures begin to dip, anxieties about what this year’s winter weather will bring for the United States begin to rise. Of all the headaches wintry weather brings, loss of electricity is the underlying cause for many of them. We are more dependent upon electricity than ever, needing it to power our computers and phones along with the internet connections that feed them. The stakes become higher the longer power is out – homes dependent on electricity for heat grow cold, while freezers full of food lose their cool. Though utility companies throughout the country cannot control the weather, there are things they can do to keep the power flowing by working ‘smarter,’ not harder, by implementing a smart grid.
To best understand how a smart grid works, it’s important to understand how a utility company handled an outage on a standard grid. A typical feeder – or hub of power distribution – serves about 3,000 customers. If power went out, the utility company had to rely on phone calls from customers to determine where outages were. Then, using push pins on a map, the company would triangulate the location of possible damage. The next challenge was to restore power, with linemen going to each feeder to manually close the power distribution switch to isolate the problem. Meanwhile, headquarters had to determine which substations in the area could handle customer loads, so power could be redirected around damaged areas to get to customers elsewhere on the grid. This process could take hours, not even counting the time it would take to make the physical repairs.
David Chiesa is the senior director of global business development at S&C Electric Company, a company that has been a global leader for over a century in the manufacturing and design of switching and protection products for electric power transmission and distribution. They have helped utility companies around the world implement smart grid solutions.
Chiesa explains that a smart distribution grid uses layered communication approach, where devices at the lowest levels communicate with each other and provide utility companies with information about outages, faster. And with a smart grid, not only are companies able to quickly determine exactly where damage may be, the system can ‘self-heal,’ meaning the system can make decisions and reconfigure the network to get as many customers back into service as soon as possible.
“The devices themselves understand when the power goes out. You don’t need the humans to call in. You don’t need the humans with the pushpins. You don’t need the humans to dispatch a truck.”
S&C Electric’s smart switches are able to measure currents and voltages and have computing power to process data that can be communicated to other devices using antennas and radios. Special processors are added so they can also communicate with other equipment on the grid.
“These devices communicate with each other all day long, so they know how much current is being carried, the capacities of the lines and the loads each substation can handle,” says Chiesa.
So maybe strong winds cause a tree branch to crash through power lines. Two smart switches detect the outage between two feeders and immediately isolate it. Then, they start comparing load and source information from other feeders, quickly determining which substations can handle the customer loads. These smart switches automatically divert power from other sources that can bypass damaged areas, getting the lights back on for customers. Though it sounds complicated, the process happens almost instantly.
“The communication can take up to eighteen seconds for the initial isolation of the fault, and then it takes 26-30 seconds for the other switches to understand the load and source information to reconnect customers into a new source of power,” Chiesa.
The physical repairs will still need to be made, but in the meantime, power outages are a brief inconvenience for the majority of customers. Winter weather causes more complicated, widespread outages with numerous problem areas that need to be restored. Utility companies work year-round to prevent these outages by “hardening” the grid with tried-and-true methods, like keeping trees trimmed and maintaining pole strength. S&C Electric’s line of products and services pair well with these efforts by giving utility companies methods for hardening the grid internally.
Many of these smart devices have moving parts which, if encased in ice, would simply not work.
“So we’ve implemented ice-breaking capabilities on these devices,” says Chiesa. “We design them to be able to overcome the amount of ice typically expected for a given area. Or, we can encase the device, putting the moving parts inside a box so it is unaffected by ice.”
Even though the lights may flicker during the next big storm, utility companies across the country will be restoring the power to more people more quickly thanks to S&C Electric’s smart grid innovations. But, Chiesa says he hopes customers don’t think about the grid too much. “Because if they don’t have to think about the grid, that means we are doing our job well.”
(Originally published on Documented Energy, November 2016, republished with permission.)