Low Resistance Grounding

Low Resistance grounding involves connecting a low resistance in series with the grounded neutral of the three phase system. Low Resistance grounding limits permits a fault current above 10A but limits it to around 50A

Low resistance Grounding is used in situations where quick operation of ground fault relay is required. This form of earthing is used when faults need to be cleared quickly.

Low resistance grounding resistors have a time rating beyond which they may not be able to maintain thermal stability due to the heat generated by the fault currents.

Low resistance grounding ensures that equipment and conductors are not exposed to the electric and mechanical stresses during an earth fault.

However, the downside of low resistance grounding is that the system needs to be de-energized after a ground fault.

These are usually used in medium and high voltage Systems

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