Here are the massive problems associated with restarting an electricity grid that has collapsed. Green proponents of the insane push for wind energy in Australia should take note. Wind energy is unreliable and can crash the grid at anytime.
Performing what is called a “black start” is no simple matter.
The primary problem is that everything that was connected to the grid when it crashed is still connected. So essentially, the Load is a “Dead Short” from the perspective of Generation.
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.
Greens ought to give the situation in Venezuela a very serious consideration before destabilizing the existing grid in any location on earth.
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.
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.
How long before South Australia becomes a Venezuela?