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 |