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China Neutral earthing transformer - Zig zag grounding transformer manufacturer

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Neutral Earthing Transformer(Zig-Zag grounding transformer) is a auxiliary transformer for transmission & distribution line protection, WEIFAN GROUP is a professional manufacturer for earthing transformer...


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Technical Tables

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China professional manufacturer of Neutral Earthing Transformer, Zig-Zag grounding transformer, or earthing/auxiliary transformer.

Neutral Earthing Transformer

The three phase Neutral earthing transformer is to provide an artificial neutral point for the system where the neutral point is not grounded, so that the grounding method of arc suppression coil or small resistance can be used to reduce the capacitance current to ground when the distribution network has a grounding short-circuit fault. , to improve the reliability of power supply of the power distribution system.
This type of transformer adopts Z-type wiring (or zigzag wiring). The difference from ordinary transformers is that each phase coil is divided into two groups and wound on the magnetic column of the phase in opposite directions. The advantage of this connection is that the zero-sequence magnetic flux can be The magnetic column circulates, and the zero-sequence magnetic flux of the ordinary transformer flows along the leakage magnetic circuit, so the zero-sequence impedance of the Z-type grounding transformer is very small (about 10Ω), while the ordinary transformer is much larger. According to the regulations, when using an ordinary transformer with an arc suppression coil, its capacity shall not exceed 20% of the transformer capacity. Z-type transformers can be equipped with arc suppression coils of 90% to 100% capacity. In addition to arc suppression coils, grounding transformers can also carry secondary loads, which can replace station transformers, thereby saving investment costs.

Features
 The zero-sequence impedance is low to ensure the output of zero-sequence current;
 High excitation impedance to reduce no-load current;
 Low no-load loss to save energy consumption in daily operation

Service environment
 Ambient temperature: -40 ℃ ~ +55 ℃.
 Relative humidity: <95%
 Altitude: less than 3000m.
 Pollution level: IV grade.

33kV,66kV class Neutral earthing transformer/Zig zag grounding transformer datasheet

Transformer Type Zig Zag Zig Zag Zig Zag Zig Zag Zig Zag Zig Zag Zig Zag Zig Zag
Rated voltage(kV) 34.5 33/0.4 33/0.4 33/0.4 33/0.415 33/0.4 30/0.4 33/0.4
vector group ZN ZNyn11 ZNyn11 ZNyn11 ZNyn11 ZNyn11 ZNyn11 ZNyn11
Neutral fault current Io=200A @ 10s Io=100A @ 10s Io=500A @ 2s Io=120A @ 2s Io=300A @10s Io=360A @10s Io=300A @10s Io=1008A @10s
Zero Sequence Impedance/ph Zo=297W Zo=95W Zo=38.1W Zo=158.77W Zo=181W Zo=158.57W Zo=50W Zo=19W
Power frequency insulation level 70 70 70 70 70 70 70 70
Lightning impulse insulation level 170 170 170 170 170 170 170 170
Refrigeration ONAN ONAN ONAN ONAN ONAN ONAN ONAN ONAN
Insulation class A A A A A A A A
loadable winding No 0.4kV 0.4kV 0.4kV 0.415kV 0.4kV 0.4kV 0.4kV
Secondary auxiliary capacity N/A 250 315 315 300 200 500 100

11kV,15kV,22kV class Neutral earthing transformer/Zig zag grounding transformer datasheet

Transformer Type Zig Zag Zig Zag Zig Zag Zig Zag Zig Zag
Rated voltage(kV) 11/0.4 15/0.4 15.75 20/0.4 66/70
vector group ZNyn11 ZNyn11 ZN ZNyn11 ZNyn11
Neutral fault current Io=500A @ 2s Io=100A @ 10s Io=3500A @3s Io=150A @10s Io=300A @10s
Zero Sequence Impedance/ph Zo=23.8W Zo=57.5W Zo=6.65W Zo=223.8W Zo=134.5W
Power frequency insulation level 28 38 38 50 140
Lightning impulse insulation level 75 95 95 125 325
Refrigeration ONAN ONAN ONAN ONAN ONAN
Insulation class A A A A A
loadable winding 0.4kV 0.4kV No 0.4kV 0.4kV
Secondary auxiliary capacity 275 160 N/A 200 800

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