Conversion of a solidly grounded system into an HRG system

A very large majority of electrical faults starts as a ground fault. On a solidly grounded power system, a ground fault has much the same potential energy as a phase-to-phase fault, can conduct thousands of amps, and can rapidly escalate into an extremely dangerous and damaging arc-flash incident. A ground fault must be interrupted immediately.

The physical differences between a solidly grounded system and a resistance-grounded system are small.  The former has a solid cable or bus connection between system neutral (X0) and earth/ground, while the latter has a current-limiting resistor connected between X0 and earth/ground.