Neutral Resistance Grounding

Set a neutral-earthing resistor (NER, resistance-grounded neutral) for a MV network: resistor current, earth-fault current, resistor rating, trip setting and sensitivity of the residual overcurrent protection (IEC 60076 / IEEE 32 / utility earthing code).

Inputs

System line voltage Uₙ kV

Neutral resistor Rₙ Ω

Network zero-seq capacitance C₀ µF

Earthing transformer Sₙ kVA

Reliability factor K_rel —

Frequency Hz

Results

Note — A resistance-grounded neutral limits the earth-fault current to a set value (typically 100–1000 A for MV) so the fault stays detectable yet non-damaging. The total fault current is the vector sum of the resistive and capacitive parts (90° apart). The tripping current is set to clear the resistive fault with margin yet stay secure against the healthy-network capacitive current; sensibility K_sen ≥ 1.5 is required. The resistor and earthing-transformer ratings are short-time (10 s) duties — verify against the supplier data and the utility earthing code.