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pdx_flyer | 1 year ago

The article doesn't say much about it but I am sure there is significant work being done at the transmission substations as well to support the extra capacity.

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ghouse|1 year ago

As the new conductors will have lower impedance, some breakers may need to be replaced to interrupt higher fault current. Otherwise, it's likely the only substation equipment needing to upgrade would be series compensation stations which may have lower normal and emergency ratings than the upgraded conductors.

More likely is that lower impedance on the reconductored circuit will cause increased flows on other, non-upgraded circuits, either requiring those to be reconductored, or installing phase-shifting tranformers or reactors to limit current.

pdx_flyer|1 year ago

Good points.

Have you seen a lot of phase-shifting transformers in the U.S.? In my experience they've mostly been in Europe with a few specialized applications in the States.

I would think a utility would want to reconductor the other circuits otherwise they're leaving benefits on the table right?

sitkack|1 year ago

If substations are being upgraded, they should also be installing batteries and inverters at the substations at the same time.

specialist|1 year ago

Spot on. David Roberts (Volts) also asked about that in one of his interviews.

IIRC, the expert answer was: substations generally need a retrofit (eg new transformer, breakers, smarts).

Even so, reconductoring is much faster and cheaper than building new lines.

Because retro doesn't require a new permit, often reuse existing footprint, and substations can be upgraded as needed (eg only for sections pushing more power).