The method used to make very high voltage devices is to design a series stack with external components to control voltage sharing. An example is the voltage trippler in crt power supplies. check out laser experiment pages and high voltage power supplies. Once you see the concept it is not to complex. The voltage dividing network must swamp out the leakage in the devices to maintain sharing so the turn on /off carachteristics will be worse than we expect at low voltage but normaly this is not an issue.

This applies to both the control devices and the capacitors.

I know that our hydro grid uses a hv > 65000 volt dc transmission line between Vancouver Island and the mainland. This is an underwater cable and DC was selected to reduce losses over the approximatly 20 mile run. This has been done before when they convert the DC back to AC. hth Terry