David Dahle's photos


  • Otter Tail Power - Dawson, MN

    The Dawson / Boyd sub after the incoming line was upgraded to 115kV as part of the 2006 Appleton-Canby project. One transformer serves Dawson proper while the second serves a large commercial customer and Boyd, MN.

  • Montana-Dakota Utilities - Bismarck, ND

    The Bismarck 'Highland Acres' sub while it still stood. All that remains is the 41.6kV branch line (to the water plant). The distribution circuits are now served out of a new 115/12.5kV sub elsewhere in town. The way it was arranged, it is very possible…

  • Montana-Dakota Utilities - Kenmare, ND

    The start of the long-downgraded segment of the 22kV line that once ran to Sherwood and Mohall. All that remains is a mile or so that takes a longer route back to US 52, then ends as a distribution line (the current 57kV line is across the road). www.ipe…


  • Montana-Dakota Utilities - Wolf Point, MT

    The heaviest of the three subs in Wolf Point. I am not 100% sure if the distribution system in this part of town was 2400 or 4160V, but the system is definitely 4160V in other parts of town.

  • Montana-Dakota Utilities - Renville County, ND

    Just another picture of the Tolley / Mouse River Park sub when it still put out 7200V delta (the sub was converted to 12.5kV output in fall 2017). Gotta love how there are NO regulators and the single circuit splits in two outside the sub, instead of eac…

  • Montana-Dakota Utilities - Sheridan County, MT

    Three 57kV lines heading downhill from the Plentywood transmission sub. The lines were shielded construction until they reached the base of the hill, then reverted to delta construction.


  • Montana-Dakota Utilities - Mandan, ND

    MDU's Heskett Station (named after MDU's founder, Rolland McCartney Heskett), along with an anchor tower for one of two lines that crosses the Missouri River. MDU plans to retire (and likely remove) the Heskett Station within the decade, due to its age.…

  • Northwestern Energy - Codington County, SD

    A long-haul line between Florence and Wallace, featuring a storm-braced structure, which is similar to some found on MDU's 41.6kV system (not surprising, as that portion of MDU's system was once a separate utility that was managed by NWPS). The third and…

  • Northwestern Energy - Mellette, SD

    Looks like NWPS was in the process of replacing a H-frame pole on its 34.5kV trunk line with a regular pole, and it is interesting to see NWPS still insists on using porcelain for its 34.5kV system, even though they use polymer on distribution circuits.


  • East River Electric - Faulk County, SD

    One of East River Electric's older 69kV lines, featuring construction nearly identical to MDU's 57kV specification. This leg of the system (between Cresbard and Ipswich) also featured recent replacement poles that could pass for Minnkota's delta specifica…

  • Montana-Dakota Utilities - Ipswich, SD

    An obviously recent replacement pole, and which has the neutral on an odd alley-arm. Yes, MDU has begun using Hendrix 15kV tie-tops for new extensions and repairs.

  • Montana-Dakota Utilities - Ipswich, SD

    Not quite sure what's going on here - the lines in this part of town could well have been 6 on the arm originally, I don't know. Or this was Northern Power & Light's original spec. Just odd.


  • FEM Electric Association - Edmunds County, SD

    Look at those CD 239 Kimbles just shining in the sun! The bulk of this line running west from the coop's Roscoe sub was still mostly on glass. I tried for a perspective shot with the sun shining on the glass insulators, but I got the sun in the shot.

  • Montana-Dakota Utilities - Edmunds County, SD

    Progress on the new Bowdle 115/41.6kV sub. As with the old one, it will step one 115kV circuit down to serve four 41.6kV circuits. The company is also adding another 115/41.6kV sub near Leola (and that one will be served by a new company-owned 115kV lin…

  • Montana-Dakota Utilities - Mound City, SD

    The switch just before the point the line turns back north into the Mound City distribution system. These switches used to be common, but are apparently getting replaced during upgrade cycles as crossarm-level switches are no longer 'best practice'.


  • North Central Electric - Bottineau County, ND

    The sectionalizer previously shown in another picture; it now becomes apparent this part of the system got an upgrade from 12.5kV to 24.9kV at one point. Sectionalizers are similar to reclosers, but gives a fault only 2 chances to clear before cycling to…

  • North Central Electric - Bottineau County, ND

    The 24.9kV recloser pole shown in another picture.

  • Montana-Dakota Utilities - Sherwood, ND

    A pole with a trio of Westies after the 4160V conversion.


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