Zig-zag Oil immersed earthing transformer 15kV 17.5kV 20kV

  • Zig-zag Oil immersed earthing transformer 15kV 17.5kV 20kV
Key attributes
Brand Vziman
Model NO. Zig-zag Oil immersed earthing transformer 15kV 17.5kV 20kV
Rated voltage 15kV
Rated frequency 50Hz
Series S
Product descriptions from the supplier
Description

Summary

Our Oil immersed earthing transformer, including Zig-zag Earthing Transformer, adopts insulating fluid immersion and natural self-cooling (ONAN) mode, three-phase design, and 50/60 Hz frequency. Suitable for indoor and outdoor use, it features hermetic sealing, CRGO silicon steel core, and high-strength cold-rolled steel tank, ensuring stable grounding protection performance.
Features
  • Power Ratings & Voltage ： Common power ratings for Oil immersed earthing transformer (including Zig-zag Earthing Transformer) are 30–2500 kVA, for voltages ≤ 36 kV. Dual primary voltages (via no-load tap changer/terminal adjustment) and secondary voltages (400V/415V/433V, customizable) are available.
  • Connection Configurations：Standard connections for Zig-zag Earthing Transformer and Oil immersed earthing transformer are Yyn0 (≤160 kVA) and Dyn11 (>160 kVA); other configurations are customizable.
  • Temperature Rise ： Per IEC/BSEN 60076, Oil immersed earthing transformer has max oil temp rise 60K, winding avg 65K; Zig-zag Earthing Transformer allows custom temp rise.
  • Oil Expansion System：Oil immersed earthing transformer (including Zig-zag Earthing Transformer) has three oil expansion systems; Vziman recommends hermetic elastic tanks for compactness and low maintenance.
Material maximum admissible voltage 12kV 17.5kV 24kV 36kV
Withstand voltage  28kV 38kV 50kV 70kV
Basic insulation level 75kV 95kV 125kV  170kV

Highest voltage for material: ≤ 12 kV

Rated capacity (kVA) HV(kV) Tapping range LV (kV) Vector group Loss(kW) No-load current (%) Impedance voltage  (%) Weight (kg)
Load loss No-load loss oil Total
10

6

10

11

±5%

or

±2*2.5%

0.4

0.415

0.433

Dyn11

or

Yyn0

 0.26 0.09 3.2 4 45 172
20 0.44  0.10 3.0 65 240
30 0.63 0.13 2.3 65 245
50 0.91 0.17 2.0 80 330
63 1.09 0.20 1.9 90 365
80 1.31 0.25 1.9 95 410
100 1.58 0.29 1.8 115 490
125 1.89 0.34 1.7 140 620
160 2.31 0.40 1.6 155 720
200 2.73 0.48 1.5 175 810
250 3.20  0.56 1.4 200 940
315 3.85 0.67 1.4 215 1090
400 4.52 0.80 1.3 240 1250
500 5.41  0.96 1.2 285 1460
630 6.20 1.20 1.1 4.5 345 1720
800 7.50 1.40 1.1 390 2050
1000 10.30 1.70 1.0 460 2430
1250 12.00 1.95 1.0 550 2850
1600 14.50 2.40 0.8 690 3600
2000 18.00 2.60 0.7 790 4300

Highest voltage for material: 15-24 kV

Rated capacity (kVA) HV(kV) Tapping range LV (kV) Vector group Loss(kW) No-load current (%) Impedance voltage  (%) Weight (kg)
Load loss No-load loss oil Total
30

15

20

±5%

or

±2*2.5%

0.4

0.415

0.433

Dyn11

or

Yyn0

 0.60 0.10 2.1 4 85 350
50 0.87 0.13 2.0 90 480
63 1.04 0.15 1.9 110 600
80 1.25 0.18 1.8 110 660
100 1.50 0.20 1.6 120 700
125 1.80 0.24 1.5 130  800
160 2.20 0.29 1.4 140 940
200 2.60 0.33 1.2 160 1130
250 3.05 0.40 1.2 180 1290
315 3.65 0.48 1.1 230 1400
400 4.30 0.57 1.0 250 1550
500 5.15 0.68 1.0 260 1780
630 6.20 0.81 0.9 320 2100
800 7.50 0.98 0.8 350 2560
1000 10.30 1.15 0.7 4.5 450 2800
1250 12.00 1.36 0.6 490 3200
1600 14.50 1.64 0.6 640 4000
2000 17.14 1.94 0.6 800 4900
2500 20.26 2.30 0.5 1180 6300

Highest voltage for material: 36 kV

Rated capacity (kVA) HV(kV) Tapping range LV (kV) Vector group Loss(kW) No-load current (%) Impedance voltage  (%) Weight (kg)
Load loss No-load loss oil Total
50

 

30

33

35

38.5

±5%

or

±2*2.5%

0.4

0.415

0.433

Dyn11

Yyn0

Yd11

 1.27    0.21 2.0 4 265 860
100 2.12 0.29 1.8 310 1150
125 2.50 0.34 1.7 320 1190
160 2.97 0.36 1.6 360 1230
200 3.50 0.43 1.5 390 1300
250 4.16 0.51 1.4 425 1480
315 5.01 0.61 1.4 460 1590
400 6.05 0.73 1.3 490 1760
500 7.28 0.86 1.2 540 2150
630 8.28 1.04 1.1 620 2380
800 9.90 1.23 1.0 780 2800
1000 12.15 1.44 1.0 850 3410
1250 14.67 1.76 0.9 950 3890
1600 17.55 2.12 0.8 1060 4620
2000 19.35  2.72 0.7 4.5 1195 5345
2500 20.70 3.20 0.6 1285  5960
3150 24.30 3.80 0.6 1470 6695
4000 28.80 4.52 0.5 1760  8350

Standard

Both Zig-zag Earthing Transformer andOil immersed earthing transformer are designed and tested in strict accordance with IEC/BSEN 60076 standards, meeting international requirements for earthing transformer performance and safety.
Construction Details 
  • Magnetic Circuit ：The magnetic circuit of Zig-zag Earthing Transformer and Oil immersed earthing transformer uses low-loss oriented plates (IEC/BSEN 60076), with 45° joints to minimize gap effects and optimize performance.
  •  Low Voltage Winding： The low-voltage winding of Oil immersed earthing transformer uses insulated wires/strips, resisting short-circuit stress (IEC 60076) and suiting Zig-zag Earthing Transformer operation.
High Voltage Winding 
  • English: Wrapped around the low-voltage winding, the high-voltage winding ofZig-zag Earthing Transformer uses circular/rectangular conductors (class H enamel insulation). Anti-resonant section design resists ray-type pulse waves, and resin-impregnated interlayer insulation ensures mechanical strength under short circuits, matching Oil immersed earthing transformer reliability.
  • Active Part： The active part of Oil immersed earthing transformer (removable from the tank) includes core, windings, fixing structure, tap changer, cover, and bushings. For Zig-zag Earthing Transformer, the active part is optimized for zero-sequence current conduction, ensuring stable grounding performance.
 Tank
The elastic tank of Oil immersed earthing transformer absorbs oil volume expansion without permanent deformation, consisting of supporting frames, base, cooling fins, and outer frame. Corrugated cooling fins (cold-rolled steel) provide elasticity, while watertight welding and pressure limiters enhance leak resistance—ideal for Zig-zag Earthing Transformer outdoor operation.
 
Documentation Resource Library
Vziman IEC/ ANSI Oil-immersed Grounding Transformer selection catalog
Restricted.
Vziman IEC/ ANSI Oil-immersed Grounding Transformer selection catalog
Catalogue
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