Power Distribution Equipment

1. What is a neutral grounding resistor

The neutral grounding resistor is the connection between the system neutral and ground. It provides a path for ground fault current to return to the transformer neutral.

2. Why we use NGR

To reduce burning and melting effects in faulted electrical equipment, such as switchgear, transformers, cables and rotating machines.

To reduce mechanical stresses in circuits and apparatus carrying fault currents

To reduce electrical-shock hazards to personnel caused by stray ground fault currents in the ground return path

To reduce the arc blast or flash hazard to personnel who may have accidentally caused or who happen to be in close proximity to the ground fault.

To reduce the momentary line-voltage dip occasioned by the occurrence and clearing of a ground fault.

To secure control of the transient over-voltages while at the same time avoiding the shutdown of a facility circuit on the occurrence of the first ground fault (high resistance grounding)

3. Features

Neutral grounding resistors are used in star connected systems to protect the transformer/alternator from severe damage caused in event of an earth fault

We manufacture neutral grounding resistor for all current ratings up to 2000A and for a voltage range from 230V to 36kV

The resistors can be designed in cast iron grid, rod formed grid, wire wound and punched grid form.

4. Advantage of using a neutral grounding resistor

Reduced operation and maintenance expense
Fast isolation of the original fault
Reduced transient over voltages
Reduced physical damage on the equipment at fault
Simplification of ground fault location
Increased life and protection of transformers, generators and related equipment
Reduced frequency of faults
Improved service reliability
Increased protection in the use of lightning arresters
Increased safety for personnel