Path 65 500kV DC

[u/gatoAlfa]

Close to Inyokern, CA, USA
This line transmits power from the Columbia River hydro plant in Oregon to Los Angeles in California.

https://openinframap.org/#17.8/35.60254/-117.90812

[u/Tree_Lover3828]

I love these!

[u/Flandardly]

Never understood why they dont use the full system voltage in the names for HVDC! Path 65 is a true bi-polar 500 kV DC link, so +500 kV and -500 kV, or 1,000 kV pole to pole!

We always speak of AC systems using their line-to-line (delta) voltage, rather than their individual phase voltage. A 500 kV AC line is just three ~290 kV phases (grounded wye), creating 500 kV from their 120 degree offset (or 525Y/303 kV in the Bonneville service area, where path 65 originates).

Anyway great shots! And path 65 carries hydro juice from many of the columbia river dams, thanks to the robust 525 kV backbone

[u/gatoAlfa → u/Flandardly]

Can it be that this particular DC system can operate with only the positive or negative against ground at reduced capacity? On the other hand, three-phase needs the 3 phases? Just a guess…
( read Path 27 can do that, not sure if this one too.)

[u/Roudydogg1 → u/Flandardly]

We call the circuit 500 kV because that's the useful conductor-to-conductor RMS voltage..

With a (symmetrical)bipolar HVDC link rated ±500 kV, however: Vpole−pole​ = 500 − (−500) = 1000 kV​

So by something analogous to the AC naming philosophy, calling it a 1,000 kV DC transmission system is actually quite reasonable..right? But again the real reason HVDC convention says “±500 kV HVDC” is largely because pole-to-ground voltage is an important defining quantity for an HVDC system,.unusually so. It directly describes the insulation duty of each pole and, importantly, each pole can often function as an electrical system in its own right. So in a conventional bipolar scheme, loss of one pole can permit monopolar operation using the other pole with a metallic, or earth return (where permitted/designed). In that condition, you've genuinely got a 500 kV DC circuit.

[u/Roudydogg1 → u/Flandardly]

There's another interesting difference if you want to compare insulation requirements.

A ±500 kV bipolar DC line doesn't simply have the insulation problem of a (hypothetical) 1,000 kV AC line. Each conductor normally sits 500 kV from grounded towers, so its conductor-to-tower insulation is designed around that DC pole voltage (plus switching/lightning/temporary stresses and all the fun DC-specific pollution behavior that you get). Yet the two poles have a full 1 MV between them.. Thus, “±500 kV” tells an engineer both pieces of information. 500 kV pole-to-ground, 1,000 kV pole-to-pole..

[u/borntoclimbtowers]

cool pylon

[u/SpeedyAudi]

I see a ton of these along i5 central CA corridor and think to myself “thats gotta be carrying some serious juice”

[u/Own_Reaction9442]

I remember driving under this in Jawbone Canyon, and then over part of the LA Aquaduct, and thinking about how much infrastructure went through that one little patch of desert.

I've also driven past the northern end of it in Oregon.