Its a pretty simple system, they use a number of isolating transformers to provide zoning of the sub systems. if its fed through an isolating transformer the power flows through bu the fault is kept isolated. Basically multiple IT systems with fault monitoring. You will see this in any safety critical system, by isolation of the system and removal of an earthed neutral the power system then floats. you can have a phase to earth fault and this will do nothing other than let the operators know. however a second fault then you will blow fuses and trip breakers, but it gives you that ride out capability, Also upon the reciept of a fault the operator will quickly remove the faulted item from the system if required. Or if in the middle of something important they can carry through until they are are a safe point to recover the issue.

Its a pretty simple system, they use a number of isolating transformers to provide zoning of the sub systems. if its fed through an isolating transformer the power flows through bu the fault is kept isolated. Basically multiple IT systems with fault monitoring. You will see this in any safety critical system, by isolation of the system and removal of an earthed neutral the power system then floats. you can have a phase to earth fault and this will do nothing other than let the operators know. however a second fault then you will blow fuses and trip breakers, but it gives you that ride out capability, Also upon the reciept of a fault the operator will quickly remove the faulted item from the system if required. Or if in the middle of something important they can carry through until they are are a safe point to recover the issue.