One can have in series a very fast solid-state relay (which would disconnect in some tens of microseconds at most; e.g. with IGBTs) and a mechanical relay for p

One can have in series a very fast solid-state relay (which would disconnect in some tens of microseconds at most; e.g. with IGBTs) and a mechanical relay for permanent disconnection. This would increase the cost, but by many times less than the insulated power converters used today.