Oil Immersed Type Grounding Transformer
1. Scope of application
Oil Immersed Type Grounding Transformer is a special transformer that provides an artificial neutral point for the power system with an ungrounded neutral point. It is mainly used to connect to the arc suppression coil or a low-resistance grounding device to suppress the capacitive current to the ground during a single-phase grounding fault and prevent arc reignition and overvoltage hazards, which includingoil-immersed and drytypes. It adopts zigzagZ-type wiring. By dividing each phase winding into two groups and winding them in reverse, a low zero-sequence impedance characteristic is formed to facilitate the flow of zero-sequence current.
The grounding transformer significantly improves the safety of the power grid by suppressing capacitive current and overvoltage, and has become an indispensable key equipment in modern power systems. Its core function is to solve the problem that the power system with Delta Connection or neutral point is not directly grounded.
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) Low zero-sequence impedance: The Z-type wiring design makes the zero-sequence magnetic flux cancel each other, and the impedance is less than 10Ω, ensuring the efficient flow of the compensation current of the arc suppression coil.
2) High-capacity utilization: It can carry 90%-100% of the capacity of the arc suppression coil, while ordinary transformers only support less than 20%.
3) Long-term operation stability: Adapt to long-term no-load and short-term overload operation, with high reliability.
4) Multi-function integration: A secondary winding can be added to replace the transformer to save equipment investment.
5) Structural simplification and cost optimization: Reduce magnetic circuit loss through Z-type connection, reduce manufacturing cost and floor space.
4. Applications
1) Distribution network system: Mainly used in 6-35kV distribution network with ungrounded neutral point, especially in the scene where the low-voltage side of the main transformer is Delta Connection.
2) Industrial distribution system: Power distribution scenes such as factories and large commercial buildings to ensure equipment insulation and power supply continuity.
3) New energy power generation: In new energy systems such as wind power and photovoltaics, suppress ground fault current.
4) Public facilities: Power systems in hospitals, schools and other places to reduce the risk of single-phase ground faults.
