10,000 PLA troops, en masse?
That’s a nice fantasy.
That is not happening.
En masse?
Not what I said or meant.
Lone wolf, 3 man teams, cyber saboteurs, etc.
A guy with a bolt cutter and satchel charge with a couple other over watch guys to eliminate any nosy guards.
It doesn't take much to damage or even destroy a transformer.
Or couple bullet holes in the radiator, oil drains out and the transformer overheats. Could be done without even entering the property, as was demonstrated between Gilroy and San Jose. That substation now sports a tall concrete wall on all 4 sides. It's the only substation I've seen that is so protected.
A Chinese made drone from Amazon with half a pound or so of Semtex.
A data spoof cross wiring outputs out of phase.
Balloons with dangling bare wires released up wind of power lines, a pickup truck with a driver, a guy with a real time weather ap to keep the release points upwind, a helium tank, a balloon filler upper guy and a a guy watching to release the balloons between the towers.
Divide the 10,000 (of how many 'got away' border crossers is it now? 600,000?) into lone wolves, 3 man teams, squads of ≈ 10, and you can take out a LOT of irreplaceable transformers at any given pre-arranged time.