[caddywompus]

I think you're right. The system expects a certain voltage, if the load increases too much, the generators would struggle to keep up, and the voltage would begin to drop.

However, the total amount of power would remain the same, which means that the electrical current would increase to compensate.

The problem is that the amount of current increase is a square law increase compared to the voltage,

V = I * R

P = V * I

P = I^2 * R

So now you have equipment having to deal with the heat created by resistance (since nothing is 100% efficient), but way more heat than it can handle.

I'm not an electrician either, and my knowledge of AC isn't great, so I'm sure there are other reasons too, like the frequency is also effected if the generator can't keep up with the load, and that causes other problems