David Dahle

David Dahle

Posted on 03/31/2016


Photo taken on March 30, 2016


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69kV
34.5kV
7970V


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Northern States Power - Sioux Falls, SD

Northern States Power - Sioux Falls, SD
Another segment of the dead 69kV line - but the distribution line here is actually that frigging 34.5kV line that serves my block and 3 others nearby.

That big can is the 19.9kV/7970V step-down serving the branch line (crossing the street).

Jesse Lor, Jim Gullett have particularly liked this photo


Comments
Justin S
Justin S
I take it you have experienced some outages associated with the 34.5 kV.
21 months ago.
David Dahle has replied to Justin S
Oh yeah. Whenever there's a major weather event this 34.5 line tends to become unstable - and even when the weather's nice there will be the occasional momentary blink. During the 2013 ice storm I was without power for almost a whole week. In the meantime the surrounding 13.8kV circuit has been rock stable in comparison - during that same storm, only individual customers lost power when their service drops were knocked loose. The only time I can think of when my neighborhood 13.8kV circuit was offline for a while was during the June 2014 windstorm that blew down one pole on this 69kV line (sending the distribution line crashing into a muni circuit, knocking both offline). What's even more frustrating is that a branch of this 13.8kV line now passes close enough to my 7970V line that Xcel just needs to replace two poles and run 3 spans of 7970V to move it off the 34.5kV system (back when this neighborhood was 4160V, it was ALL one feeder).
21 months ago.
Justin S
Justin S
Sounds like a bit of a mess there- actually very similar to many setups around here. The 34.5 kV system around here is about the same. There are a lot of automated switches and stuff but the circuits are long and serve a lot of customers over a large area. Recipe for the problems you describe. I'm thankful I'm on the 13.8 kV system, very few outages and problems.
21 months ago.
Jesse Lor
Jesse Lor
Question: are the problems associated with the 34.5kv systems involving too many customers on a circuit?
21 months ago.
David Dahle has replied to Jesse Lor
Not that they have too many customers, but rather that they cover so much more territory than the 13.8kV circuits can, which in turn exposes more territory to outage situations when trouble develops.
21 months ago.