*Would you explain me diffrent way and more that I could understand. Thank you*

Go back to basic electricity 101.

Power is the product of voltage and amps. (VA) if power factor is 100% then VA = Watts

That is what power is for electrical applications, power is also equal to amount of work being done, and this view of power is seen on the prime mover that is driving the generator. You can not get more power from the prime mover then it is able to deliver, you can change output voltage to any level you want, but the current is also going to change proportionally at any power level.

If you have 200 amps @ 240 volts(single phase) you have 48,000 VA of power.

If you transform to 480 volts at the same level of power you will only have 100 amps of current.

If you transform to 120 volts at the same level of power you will have 400 amps of current.

Power in all three examples above is still the same, voltage and current is what has changed.

A generator (or other source) doesn't generate volts, it doesn't generate amps, it generates power which is the sum of the volts and amps. All you have to do to change volts is change the number of turns in the windings, and the amps will change accordingly. The size of conductor used for the windings and amount of insulation necessary will depend on how much voltage/amps the unit is designed for. But for the generator to be able to deliver more power at any voltage you must also have a prime mover capable of delivering that power. Carry this to the distribution equipment in question here and you still have a lot of the same things. The conductors can carry higher power if the voltage is increased, but the source transformer is still limited to same maximum output power no matter what you do for conversions on its output side. If you changed the source transformer to a bigger one then you have a stronger link in the chain and can get more power, but there eventually becomes a point where you can only go so much larger and then the supply side of that transformer will reach it's limitations