After a natural disaster such as a hurricane, how do the power utilities determine where to send linemen to most efficiently restore power?
In: Technology
There will be an emergency plan that lists the priority of services being connected, likely starting with connecting the grid backbone to ensure a black start (if power stations were impacted) will be successful since power plants also need the power to be operational. Then, they would likely follow high-priority buildings such as hospitals. Residences would likely be the last to be connected.
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How all of this works could be subjected to legal requirements. Or voluntary agreements between the power company and local authorities. Or just a matter of acting according to what is most financially sound.
First of all, there may be laws that request that certain things get their power restored first. Hospitals. Waterworks. Treatment plants. Care facilities. and things like that.
Second, the power company may have received a list of “priority addresses” from a local municipality authority; service homes. Daycare facilities. Public bath houses. Schools. That kind of thing.
Second and a half, It’s also often considered A Good Thing^tm to make sure that traffic lights function, because traffic will be a mess not just for the general public, but also for the power company and various rescue services. Everyone benefits from giving this small detail some attention, even though it sounds kind of dumb.
Third, the power company may themselves have realised that since they can’t do everything, it’s wise to give some priority to things that makes people…you know…less upset that everything in their freezer is getting rotten. Which means that they may put higher priority on gas stations and bakeries and restaurants and grocery stores than a thousand villas in a suburb. Because it means that people can still get by, somewhat. Instead of most definitely not being able to.
Fourth, there may be financial incentives for making sure that as many customers as possible regain their power as soon as possible. Not just because they start to pay money for consumption again, but also because there may be laws that force the power company to forfeit income if the outage lasts too long. This means, typically, that spending ten hours restoring power for 100 customers is more worth than doing ten small on-hour jobs that restore power for 99 customers in total. I.e, the faults that get low priority are the ones with the lowest impact on the restoration progress.
Along the way here, it’s also super-important in the beginning that the line workers spend their time actually being line workers, instead of being truck drivers. Which means that no matter which direction you send them off in, you make sure to give them ALL of the work orders from a certain suburb/direction so that they can spend time fixing as much shit as possible there, instead of driving back-n-forth for no particular gain.
Since the power is out, you also have problems with actually communicating with your workers. Cell towers, radio towers for comms radios and all kinds of stuff have flakey availability. You need to give them work orders on paper, in a binder, and get to hear about the end result the morning after.
The high voltage lines have monitor systems. The network operations centre probably knows pretty well what’s wrong with it and can send crews out to fix the known issues.
But with the low voltage lines, they depend on the general public (or the affected customers) to call in a problem so that they actually know that there is one. This phonecall, obviously, will be a true pain for everyone involved. When you call them, have your lastest electrical bill in front of you, because there are some identifying numbers on it that they need to speed up the process of accepting your report. You’ll wait on the line for hours anyway, try to make it quick when you get through…
I actually used to do this!
The first part of the process involves visually inspecting the circuits to see where the problems are. This determines what sort of truck is needed, replacement parts, etc.
The next part is the tricky one – at my utility, we call it “work packaging.” Basically, we have a list of all the outages and how many people are affected by each one. We also know if they’re on a critical circuit, like one that serves a hospital or police station. If the outage involves wires on the ground, that also bumps up the priority. We would assign jobs to the available trucks based upon the capabilities of the trucks (e.g., if a new pole is needed, the truck needs to have an auger). Mainly, we try to restore as many customers as possible as quickly as possible, giving priority to critical infrastructure and life safety systems. Outages that are physically close to each other also tend to get assigned to the same trucks. There’s a bit of an art to it.
The line crews then go to work on repairs. At the end of the day, the process is repeated, and any jobs that were not completed get reassigned to new crews the following day. This process gets repeated each day until everyone is restored.
Here in Pittsburgh, our power company has you self-report on their website via cell phone (where your address is given) if the power goes out, and usually within an hour they have a physical map posted online of how widespread the outage is, how many customers are affected, and how soon it will be restored. Usually the power is back on sooner than they state. Apparently the self-reporting is a big thing to help them know specifically which houses are affected and to narrow down how and where they will send trucks, as it helps to establish a boundary/checkpoint.
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