Outdoor Neutral Grounding Resistor

Limiting earth‑fault current for equipment safety protection: When a single‑phase earth fault occurs in the system, it limits the fault current to a safe and controllable range, preventing heavy current from burning out transformer windings, cables and switchgears, and averting the fault from escalating into a phase‑to‑phase short‑circuit.

Suppressing arc‑grounding overvoltage and reducing fire and explosion risks: System earth faults are prone to producing intermittent electric arcs, which induce overvoltage several times the rated voltage and break down equipment insulation. By injecting resistive current, the neutral‑grounding resistor quickly extinguishes electric arcs and suppresses overvoltage. It safeguards system insulation and prevents accidents including cable‑joint explosions and switchgear fires.

Enhancing protection‑device sensitivity to enable rapid fault location: It keeps the fault current at a level detectable by relay protection devices. Working in coordination with the protection system, it achieves rapid tripping and location of faulty feeders, reduces the scope and duration of power outages, and improves power‑supply reliability.

Stabilizing system voltage and mitigating electromagnetic interference: It curbs voltage rise on healthy phases during faults to avoid adverse impacts of overvoltage on the operation of other equipment. At the same time, it reduces system zero‑sequence current and mitigates electromagnetic interference to communication and weak‑current equipment.