High Resistance Grounding (HRG) systems limit the fault current when one phase of the system shorts or arcs to ground, but at lower levels than low resistance systems. In the event that a ground fault condition exists, the HRG typically limits the current to 5-10A.
Earthed neutral in the secondary side of Tx to from a TT earthing system is required as per local code requirement. There is a debate about whether it is necessary to provide PVC sheath conductor or just bare conductor for the earthed neutral (i.e. from the star point to the earth electrode).
A grounding transformer or an earthing transformer is used to provide a ground path to either an ungrounded way or a delta-connected system. Uses: It provides a relatively low-impedance path to ground, thereby maintaining the system neutral at or near ground potential.