Assuming it isn't a blatant lie they could be talking about peak-to-peak which is a common deception used to sell audio gear. You know those little home systems that claim 200-400 watts, most are under 50 watts RMS which is the true power as opposed the peak-to-peak power which means nothing but is often quoted as it's much bigger.
Assuming that 300kW is peak-to-peak for a sine wave it won't be as they can claim bigger numbers by using square waves it would be about 212kW RMS. We can then take 212,000 W and divide by 200v (the upper end of spear voltages) and we get 1060 Amps.
This could be done but it wouldn't be easy or cost effective and would need insane cooling for the amps.
With large generators or in a mid-sized factory this power would be available but I call shenanigans.
It's much more likely they are running around 40kW RMS with 200 amps at 200 volts and they have just taken their peak-to-peak measurement with the most favorable waveform.