Marc Brooker

There’s a wind storm around, so today I’m thankful for reclosers, one of my favorite parts of electrical infrastructure.

Reclosers are part of the electrical distribution system, the “medium size” electrical network that bridges between the big steel tower 400,000 volt world of electrical transmission and the happy little 110v power in your home. They’re like the circuit breakers that turn your power off if something bad happens to your home wires, but have a special trick up their sleeves.

Dec 28, 2022 at 3:13amWeb
Show threadMarc BrookerDec 28, 2022

Out in the distribution world, a very high percentage of bad things that happen to electrical lines are short-lived, like bird poo, falling branches, lightning, and grilled squirrels. Reclosers watch the lines carefully, and can turn current off in tens of milliseconds if one of those things happens.

Then, a couple seconds later, they turn it back on automatically. Mostly the transient badness has passed, and the network can go back to normal operation.

Show threadMarc BrookerDec 28, 2022

No need to send out a crew in a storm, apologize to customers, or sit in the dark. The little computers in reclosers reduce end-user power outages by something like 80%, at a very reasonable cost.

You’ve probably sat at home in a wind storm (or ice storm, like we had the other day in the PNW) and had your power go out for a couple seconds before returning. That’s likely a recloser at work.

Show threadMarc BrookerDec 28, 2022

Like any good control system, reclosers limit the number of times they try. Normally something like 2, 3, or 4 times. Once they’ve tried a few times, they decide that the line is down, or needs repair, and don’t try again. Sometimes they back off too.

Reclosers have been around since the 40s, and popular since the 70s, but are still getting better. One area of improvement is in detecting “high impedance” faults, like lines touching dry obstacles.

Show threadMarc BrookerDec 28, 2022
Speaking of bird poop, did you know it comes out of the bird in a long stream rather than as a pellet? Those streams are perfect for bridging between power lines, or across insulators, a risk to both infrastructure and birds.
Show threadMurali BrahmadesamJan 7, 2023

@marcbrooker

Following is what I know about bird poop and power lines 😎

Show threadReach for the Stars Dec 28, 2022
@marcbrooker The recloser in the small town I grew up in tried 3 times with about 60 seconds between each try. It got to the point in our family when the power went out we'd start counting the tries. If it didn't stay on after the third try we got out the candles and the camp stove.
Show threadGordon GuthrieDec 28, 2022
@marcbrooker in Trinidad in the 50s the problem was Lover Birds - so called because they touch their beaks in a kiss
Show threadKevinDec 28, 2022
@marcbrooker this is like jiggling the handle on the toilet, right?
Show threadRob RicciDec 28, 2022
@marcbrooker I love this thread so much
Show threadMichael ColladoDec 28, 2022
@marcbrooker sadly for me, they don’t work actual magic https://hachyderm.io/@peladocollado/109589387961110194
Michael Collado (@[email protected])

Attached: 1 image Guess where my house is on this map of current power outages in the city 😡🕯️

Hachyderm.io
Show threadkurtshDec 28, 2022
@marcbrooker This thread deserves boosting & applause. Nice work!
Show threadVerdant Suburban RoadwaysDec 28, 2022
@marcbrooker how likely are they to start a fire in a dry forest if a tree falls on the lines or if a line hits the ground? I am hoping there is some sort of ground fault detection like residential wiring. California is a real, real dry place in the summer time.
Show threadMarc BrookerDec 28, 2022
@makewayfortrucklings
My understanding (and I've been out of this field for the best part of 20 years) is that transmissions tends to be the high fire risk, less than distributions. Reclosers do have ground fault detection (but a different mechanism from the differential way GFCIs work).
Show threadVerdant Suburban RoadwaysDec 28, 2022
@marcbrooker the distribution lines in the Santa Cruz mountains do a fair bit of snuggling up to trees. A fair number of residents also tend to shoo our utility company away when clearing the right of way, and the utilities here have been using the no maintenance plan not even the deferred maintenance plan. Developing reclosers that can communicate with each other and employ a reclose handshake to determine if the lines are clear before restoring power would bring some peace of mind.