DC used in power distribution

The actual "link" is a very interesting story, considering that local power producers were against it when J.F.K. proposed it. Upon utilization, it saved the area producers $600,000 a day, way back in

The word for today is:

VALVE (that's what they used to call the Mercury Arc Rectifiers used there)

Now, they use huge stacks of Siemens light-triggered thyristors (MARP replacement).

Ignitron. Not you, the rectifiers.

John

F*ck off, LarkinTard.

We used what was called an ignitron in LASER application to dump a cap bank into a flash lamp; it acted similarly to an SCR or, if you are familiar with tubes, a thyratron.

This has an analysis of the different reasons for HVDC transmission about half-way down the page.

The Summary section covers: In a number of applications the advantages of HVDC makes it the preferred option over AC transmission. Examples include:

a.. Undersea cables, where high capacitance causes additional AC losses. (e.g. 250 km Baltic Cable between Sweden and Germany[7]). b.. Endpoint-to-endpoint long-haul bulk power transmission without intermediate 'taps', for example, in remote areas. c.. Increasing the capacity of an existing power grid in situations where additional wires are difficult or expensive to install. d.. Allowing power transmission between unsynchronised AC distribution systems. e.. Reducing the profile of wiring and pylons for a given power transmission capacity. f.. Connecting remote generating plant to the distribution grid, for example Nelson River Bipole. g.. Stabilizing a predominantly AC power-grid, without increasing maximum prospective short circuit current. h.. Reducing Corona discharge (due to higher voltage peaks) for HVAC transmission lines of similar power i.. Reducing line cost since HVDC transmission requires fewer conductors (i.e. 2 conductors; one is positive another is negative)

The ABB group in Sweden makes a lot of these systems. It's web page on Ultra HVDC has pdfs covering many aspects of the systems.

Robert

The Pacific Intertie is single-ended; i.e. it uses ground return. If my button-pushing is correct[1], it's 6300 Amps of same.

I can't see how that is right, but even at 10% of that, it's a chunk of current to dissipate. It must FUBAR cathodic protection on anything buried within a hundred mile wide path....

The southern ground point is in the Pacific Ocean. Bet it keeps the fish away...

One of the most important reasons for using DC in a link is hinted at in the article, "improving reliability of the Bay Area power grid." That's because when converting from AC to DC and back again, one gains complete control of the frequency and phase, and hence complete control of the power transfer, preventing runway power transfers in grid-failure situations. If there are enough DC links we can go a long way toward preventing uncontrolled rolling blackouts, etc.

Not really. Rolling blackouts are load shedding.

What DC Interties do is help prevent domino-type failures such as the two NE blackouts and the more recent Midwest->NYC one.

Looks like you got one right.

I am surprised that you, of all people, made that mistake. "Rolling blackouts" are a thing that is done on purpose. You don't get uncontrolled ones. When there is no control, you usuually get just "blackouts". They may be "jumping backouts" "random blackouts", or "sudden blackouts" but they never ever roll.

One downside to DC power lines is that they make the system harder / more complex to restart after a major failure. The load end needs power to be able to run.