I'm with Swedish on this one, will all B787 operators/line stations require >140KVA GPUs?
No because there are FOUR GPU sockets.
It really depends on how frequency sensitive they are. We have big problems here with old GPUs on the B777. A GPU that can easily handle any narrow body has problems with the B777 because of the high loads, and narrow frequency range the aircraft will accept. We always use two GPUs, and have no problems with modern FEP. But most of our stands have only a single FEP, so the second ground power must be a mobile diesel one. Of the ten that our handling agent has, only one will stay on line reliably. But they all work on other older aircraft ( and A320s B737NG etc.)