Neutral Earthing resistor systems protect power transformers and generators from damaging fault currents. Earthing of the neutral limits the ground fault current to a high level (typically 50 amps or more) in order to operate protective fault clearing relays and current transformers. These devices are then able to quickly clear the fault, usually within a few seconds. The importance of this fast response time is that it:
Limits damage to equipment
Prevents additional faults from occurring
Provides safety for personnel
Localizes the fault
UL Listed
CSA approved up to 7200v
Seismic Zone 4 Certifications and type tests also available
The limited fault current and fast response time also prevent over-heating and mechanical stress on conductors. Please note that, like the solidly earthed neutral system, the circuit must be shut down after the first ground fault. Neutral Earthing Resistors are typically rated 400 amps for 10 seconds, and are commonly found on medium and high voltage systems.
Features & Capabilities:
Neutral Earthing Resistors protect power transformers and generators from damaging fault currents
Available for systems rated 240v to 72kv line-line (CSA approved up to 7200v)
Stamped stainless steel grid or edgewound design
Current ratings up to 5000 amps
All Neutral Earthing Resistors designed and tested per IEEE32
Certified test reports and installation/maintenance instructions accompany each Neutral Earthing Resistor
Standard ventilated enclosures are painted or mill-galvanized, with stainless steel, hot-dipped galvanized, and aluminum as options
PGR will gladly package CTs, PTs, disconnect switches, earthing transformers, and heaters in the Neutral Earthing Resistor cubicle
Seismic zone 4 certifications and type tests also available
Technical papers on the theories of Resistance Earthing readily available
