Disabled Recloser Loop Schemes

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mbrooke

Batteries Included
Location
United States
Occupation
Technician
Obviously you've got main line circuits with damage from start to end. Won't deny it. However I can't help but notice what appear to be single trouble spots causing 2000-4000 customers to lose power where as this company typically has smart devices between every 500 customers.


https://outagemap.eversource.com/external/default....


Am I just biased or did they disable SCADA reclosers during tropical storm Isiasis letting substation breakers clear the whole line instead? Or at least disable normally open tie points from picking up lost load? If so what advantage would this bring? On the surface I'd think such an act would cruel to customers even if it lets them say "hey, we restored 200,000 customers in the last few hours" when this could've been done automatically during the storm.
 

Electricmo

Senior Member
Location
Missouri
Occupation
Lineman
First off restoring power automatically in a storm doesn’t usually happen. Transmission companies usually have loops to substations. They can usually isolate faulted feeders and back feed between subs fairly quickly. Distribution is usually a lot more congested and fault sensitive. Back feeding automatically without really identifying what or where the fault is could cause total loss of all feeders out of a substation. Companies don’t usually shut power off voluntarily.
 

GoldDigger

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Staff member
Location
Placerville, CA, USA
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Retired PV System Designer
But out in California PG&E is shutting down transmission lines for days at a time to prevent electrically ignited fires during times of highest wildfire danger. Causing a run on generator rentals and sales.
 

Electricmo

Senior Member
Location
Missouri
Occupation
Lineman
But out in California PG&E is shutting down transmission lines for days at a time to prevent electrically ignited fires during times of highest wildfire danger. Causing a run on generator rentals and sales.
California is a different country as far as I’m concerned . Crazy things they do out there.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Obviously you've got main line circuits with damage from start to end. Won't deny it. However I can't help but notice what appear to be single trouble spots causing 2000-4000 customers to lose power where as this company typically has smart devices between every 500 customers.


https://outagemap.eversource.com/external/default....


Am I just biased or did they disable SCADA reclosers during tropical storm Isiasis letting substation breakers clear the whole line instead? Or at least disable normally open tie points from picking up lost load? If so what advantage would this bring? On the surface I'd think such an act would cruel to customers even if it lets them say "hey, we restored 200,000 customers in the last few hours" when this could've been done automatically during the storm.
Storms are different altogether with self healing.
think of a loop scheme. A tree falls 1/4 mile from the station on left leg of the loop. It’s a hurricane... tree falls 3/4 mile from station on right leg.. how many legs they got?
I have been in storms and had to clean up lines where trees are on about every span.

Many linemen have been to locations where the ENTIRE SYSTEM is down. No fault of the POCO, just hard to keep the system up when a hurricane centers your territory.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
First off restoring power automatically in a storm doesn’t usually happen. Transmission companies usually have loops to substations. They can usually isolate faulted feeders and back feed between subs fairly quickly. Distribution is usually a lot more congested and fault sensitive. Back feeding automatically without really identifying what or where the fault is could cause total loss of all feeders out of a substation. Companies don’t usually shut power off voluntarily.

Not if the tie has over current protection- any reclose into a fault would trip the tie back out. These are recloser with cooper form 4 and above controls.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Storms are different altogether with self healing.
think of a loop scheme. A tree falls 1/4 mile from the station on left leg of the loop. It’s a hurricane... tree falls 3/4 mile from station on right leg.. how many legs they got?
I have been in storms and had to clean up lines where trees are on about every span.


Right- loss of source (preferred source), loss of tie (alternate source). Healthy segment has nothing to connect to on either side. This I can understand. No brainier.

However I'm talking about where the other side of the tie is still live and a healthy segment can be picked up from that.

Connecticut just had a news briefing with Governor Lamont and an Eversource director of distributions saying 100,000 customers had recently been restored via remote switching.

Sounds like they disabled all the loop schemes, and only just now after 24 hours are isolating and picking up what can be picked from remote switching. Think that is unfair to all the customers who could have avoided an extended outage.




Many linemen have been to locations where the ENTIRE SYSTEM is down. No fault of the POCO, just hard to keep the system up when a hurricane centers your territory.

Don't get me wrong. In some towns every circuit is damaged. There are 10 mile circuits with literally every quarter mile having a dozen broken poles. Ditto with all the tie segments. All sources unavailable. This is not what I have in mind though.
 

Electricmo

Senior Member
Location
Missouri
Occupation
Lineman
Not if the tie has over current protection- any reclose into a fault would trip the tie back out. These are recloser with cooper form 4 and above controls.
Loop feeds have normal cuts or opens here on our system. We don’t have normally open breakers sitting at our cuts here. We have knife blades or GOAB switches that need to be manually closed. All our Cooper form 4’s are at the subs.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Loop feeds have normal cuts or opens here on our system. We don’t have normally open breakers sitting at our cuts here. We have knife blades or GOAB switches that need to be manually closed. All our Cooper form 4’s are at the subs.

For your utility. Eversource has reclosers between every 500 customers 95% of them in loop scheme.

In fact they are now trying to get devices between every 166 customers:


 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Loop feeds have normal cuts or opens here on our system. We don’t have normally open breakers sitting at our cuts here. We have knife blades or GOAB switches that need to be manually closed. All our Cooper form 4’s are at the subs.

Here is my supporting reference and their philosophy:

https://energycentral.com/c/iu/dscada-talk

The company has determined that the optimal setup in its protection scheme is for each recloser to serve about 500 customers with each recloser located a few dozen yards apart in densely populated cities to perhaps miles in the remotest regions.

Those paths are on display at its system operations center in Berlin, Conn., roughly the geographic center of the state. The system operation center has divided Connecticut into three regions—western, central and eastern—with 11 individual work stations that can be reoriented as the workload demands.

Each monitor can hone in on any color-coded recloser in the system, with red and green signifying those closed and open, and white designating those not yet enabled with DSCADA. In that instance, a truck would have to roll to the site to de-energize a line. A steady stream of single-line messages scroll down another screen, monitoring events in the systems, with bright pink ones indicating messages from 911 that warrant attention and may require immediate action. On routine spring day, the center is fairly quiet, but operators are poised to act, especially when storms gather and system events literally track from west to east in a storm's path.

Don't get me wrong. Most utilities just have manually operated gang operated disconnects and cutouts- many lines being radial as well.
 

Electricmo

Senior Member
Location
Missouri
Occupation
Lineman
Seems to me automatically closing in breakers without line inspection is a way to get people killed. I’ve seen video of lines down in a storm laying in the street underneath debris obviously dead that suddenly become energized long after the initial 3 breaker operations. I always chalked it up to faulty equipment. But now I’m wondering if it wasn’t the idiot in the control room operating the scada in a panic trying to turn breakers on.🤔
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Seems to me automatically closing in breakers without line inspection is a way to get people killed. I’ve seen video of lines down in a storm laying in the street underneath debris obviously dead that suddenly become energized long after the initial 3 breaker operations. I always chalked it up to faulty equipment. But now I’m wondering if it wasn’t the idiot in the control room operating the scada in a panic trying to turn breakers on.🤔


Most likely someone in the control center trying to get the lights back on.

I do get your point there- the more you try to keep the system energized the more probability of live hazardous conditions.
 
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