NGR Sensing Resistors are attached in parallel to the neutral grounding resistor. The sensing resistor allows a protective relay to detect a resistor failure in a continuous manner.
Sensing Resistors are used in combination with neutral grounding resistor monitor relays. The relay measures neutral grounding resistance, neutral grounding resistor current and neutral to ground voltage. The relay continuously measures neutral grounding resistor ohmic value in an unfaulted system and it trips on if neutral grounding resistance varies from its calibrated value.
Sensing Resistors are used to monitor the voltage drop on the neutral grounding resistor continuously and in case of a continuity failure on the NGR, the monitoring relay trips as per the preset current and time.
Hilkar sensing resistors are used both for sensing resistor purposes to check the neutral grounding resistor continuity in addition to be used as a resistive voltage divider. When they are used as resistive voltage dividers, voltage measurement is done through the R1 and R2 terminals of the resistive voltage divider.