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Power collapses again in Venezuela

Posted By Jo Nova On March 29, 2019 @ 1:18 am In Electricity,Global Warming,Grids | Comments Disabled

What a mess. The power is down again in more than half the country — coming and going. People are desperate for water. Schools, industry and state buildings are closed. The Russians have sent in troops. The US has told them to get out.

It’s easy to take civilization for granted — until you don’t have one.

 

h/t to Rafe Champion, who links on Catallaxy to my post on how hard it is to restart a grid. And also to Lance’s comment which was so useful I added it as an update to that post and which is now starring on Catallaxy too .  In case you missed his comment, and because it’s so apt, here it is again:

Lance predicted this could take 3 – 6 months to restart (and scored 67 thumbs up)

This is a teachable moment. Smart people will pause and reflect upon what is happening, lest it happen elsewhere. This is not a game sane people want to play. Societies melt down in a matter of days to weeks without electric power, water, food, transportation, communication, etc.

We’ve yet to see how bad this is going to get. It will get a LOT worse before it gets better.

My guess is it will take 3 to 6 months to restart the grid in Venezuela, even if things go swimmingly. If a few substations and alternators are blown out, it could take 2 years. Longer if some turbines are damaged.

Substation transformers are custom made to order. They do not exist “in stock on hand” at the power levels needed on a national grid scale. Unit substations might be available in smaller sizes, say 50 to 100 MW. But the high voltage and higher power switchgear and transformers can be a 1 to 2 year lead time item even if you have the cash to pay for them.

Why startups can pull awesome loads, wild variations, and are risky and sometimes explode:

Every inductive load (induction motors) takes 6 times the normal running current to start each and every one. In terms of real and imaginary (complex) power components, the Load appears to be almost purely inductive with a Real component vector of nearly zero.

Essentially, Generation must provide 6 times the power it was providing when the grid failed and that reserve simply doesn’t exist. So energizing a substation is an explosive event.

The safest / only way to restart the grid is to isolate all of the loads except residential loads and bring up the lower voltage substations (10 kV) gradually in a controlled fashion. The residential load has resistive components ( water heaters, clothes dryers, cooking ovens, etc ) that help reduce the inductive component and provide a unity power factor component to the apparent load.

Only after the lower voltage grid is stabilized can the higher voltage transmission lines and substations (110 kV to 750 + kV)be re-energized. Even so, it is a precarious dance of balancing generated power with apparent power.

When the generator is connected to the load, it “sees” a reflected wave coming back to the generator that trips the overload safeties and causes the turbine/alternator to disconnect if the apparent power exceeds safe limits. If those safeties aren’t functional, the risk is an exploding substation, alternator, sheared turbine shaft, etc.

This is a nightmare scenario. No sane person ever wants to “smoke test” a power grid by trying a black start. The ramifications are frightening.

This is specifically why keeping a stable grid operational is a lot smarter than trying to roll the dice with intermittent generation and sudden changes in loads.

Twitter – Netblocks

See also The IP Observatory

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