What is High resistance grounding resistor and where it is being used?
High Resistance Grounding Resistors are recommended for installations that require continuous service even after a phase ground fault occurs.
A phase to ground fault will not cause a large current to flow and will not trip the breakers because the neutral grounding resistor will limit the current to a very low value, typically 5 Amps.
For added security it is required that a suitable ground detection device, or ground fault relay, be used to indicate the presence of a ground fault.
Pulsing devices can be used with high resistance systems to reduce the time required to find and remove the ground fault.
This type of Neutral Grounding Resistor should limit the fault to a value greater than the capacitive charging current of the system to avoid over-voltages caused by intermittent faults. While the disturbance lasts the resistor must be capable of absorbing and dissipating the energy generated without exceeding the temperature limits established by IEEE-32 standards.