Transformer or Generator Neutral Grounding Resistor Cabinet
1. Scope of application
Transformer or Generator Neutral Grounding Resistor Cabinet is a key device used in power systems to limit single-phase grounding fault currents and suppress overvoltage. It is usually composed of grounding transformers, resistors, switchgear, monitoring and protection units, etc. The core functions include:
Fault current limitation: The grounding fault current is limited to a safe range of 10-400A by preset resistance values to avoid thermal damage to the equipment.
Overvoltage suppression: The overvoltage caused by single-phase grounding faults is limited to less than 2.5 times the phase voltage to reduce the risk of insulation breakdown.
Fast protection action: Provide resistive zero-sequence current signals to trigger the relay protection device to quickly cut off the fault line.
2. Operation environment
1) Altitude: ≤1000 meters.
2) Ambient temperature: Maximum +40oC, Minimum -40oC.
3) Max outdoor wind speed: ≤45m/s.
4) Max Ground ramp degree: ≤3°.
5) Seismic level: ≤3m/s2 at horizontal direction and ≤1.5m/s2 at vertical direction.
6) Installation environment: No obvious and heavy pollution, no explosive and corrosive gas and dust, with good air ventilation and no severe vibration and shock.
7) If the application environment is different from the above standard conditions, please contact for customized designs.
3. Product advantages
1) Compact structure and modular design
Integrated Z-type grounding transformer, stainless steel/nickel-chromium alloy resistors and other components, using a closed metal cabinet, high protection level, easy installation and maintenance.
2) High-performance materials and high temperature resistance
The resistors are made of high-temperature resistant materials (up to 1600℃), with a temperature coefficient of ≤-0.045%/℃, stable resistance and corrosion resistance.
3) Intelligent monitoring and remote control
Equipped with current transformers, temperature sensors and intelligent controllers, real-time monitoring of neutral point current, temperature and other parameters, and support MODBUS/IEC61850 communication protocol remote data transmission.
4) Multiple safety protection mechanisms
Through the damping resistor to discharge the system residual load, suppress arc grounding overvoltage and ferromagnetic resonance, and reduce the operating overvoltage amplitude37.
5) Economy and compatibility
Reduce the insulation level requirements of the power grid, reduce the equipment investment cost by 10%-20%, and adapt to 6-66kV neutral point grounding system and new energy scenarios.
4. Applications
1) Power distribution network
Used in urban cable-intensive power grids to limit single-phase grounding fault current and suppress resonant overvoltage.
2) New energy systems
Balance capacitive current in wind farms and photovoltaic power stations to protect generator stator windings from high current damage.
3) Industry and infrastructure
Applicable to high-voltage distribution systems and data centers of chemical and metallurgical enterprises to prevent equipment failures caused by cable aging or lightning strikes.
4) Generator protection
Used for neutral point grounding of large generator sets in hydropower stations and thermal power plants to improve system stability and reduce failure rates.
