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SZ20-3150/35 On-Load Regulating Power Transformer 3150 kVA 35kV
SZ20-3150/35 is a three-phase oil-immersed on-load regulating power transformer rated 3150 kVA, stepping 35 kV down to 10.5 kV with a Yd11 vector group. Its on-load tap changer offers nine positions at ±4×2.5% (38500 V to 31500 V) so output voltage can be corrected while the transformer stays energised. ONAN cooling, a sealed steel tank with TIG-welded seams, multi-fin radiators and a dual-pointer temperature display suit continuous outdoor duty in factory distribution, construction temporary power and rural grid renovation.
- Product Model: SZ20-3150/35
- Rated Capacity: 3150 kVA
- Rated Voltage: 35000 ± 4×2.5% / 10500 V
- Rated Frequency: 50 Hz
- Phases: 3
- Vector Group: Yd11
- No-Load Loss: 2743 W
- Load Loss: 22321 W
- Cooling Method: ONAN
- Operating Condition: Outdoor
- Impedance Voltage: 6.80 %
- Insulation Level: LI 200 AC 85 / LI 75 AC 35
- Active Part Lifting Weight: 3750 kg
- Oil Weight: 1650 kg
- Total Weight: 7590 kg
SZ20-3150/35 is a three-phase oil-immersed on-load regulating power transformer built for 35 kV distribution networks. It delivers 3150 kVA at a 35000 V / 10500 V ratio with a Yd11 vector group, and its on-load tap changer moves between nine positions while the unit stays energised, so the downstream voltage is corrected without a shutdown.
Key Features
- On-load voltage regulation — nine tap positions from 38500 V to 31500 V in 875 V steps, changed under load with no interruption to supply.
- ONAN oil-immersed cooling — oil-immersed coils and core with multi-fin radiators keep the temperature rise low and support stable full-load operation.
- Sealed tank — steel welded tank with tight TIG seams, oil-resistant gasket and a bottom drain valve for long-term leak-free service and easy oil changes.
- Ceramic HV insulators — dark brown ceramic bushings with a smooth surface for stable high-voltage insulation.
- Dual-pointer temperature display — a black needle shows the current oil temperature and a red needle marks the set limit for quick visual monitoring.
- Outdoor construction — rated for outdoor operating conditions, with a red handwheel drain valve that allows oil changes without disassembly.
Tap Position and Voltage
| Tap Position | HV Voltage (V) | HV Current (A) | LV Voltage (V) | LV Current (A) |
|---|---|---|---|---|
| 1 | 38500 | – | – | – |
| 2 | 37625 | – | – | – |
| 3 | 36750 | – | – | – |
| 4 | 35875 | – | – | – |
| 5 (rated) | 35000 | 51.96 | 10500 | 173.2 |
| 6 | 34125 | – | – | – |
| 7 | 33250 | – | – | – |
| 8 | 32375 | – | – | – |
| 9 | 31500 | – | – | – |
Technical Parameters
| Item | Value |
|---|---|
| Product Model | SZ20-3150/35 |
| Rated Capacity | 3150 kVA |
| Rated Voltage | 35000 ± 4×2.5% / 10500 V |
| Rated Frequency | 50 Hz |
| Phases | 3 |
| Vector Group | Yd11 |
| No-Load Loss | 2743 W |
| Load Loss | 22321 W |
| Cooling Method | ONAN |
| Operating Condition | Outdoor |
| Impedance Voltage | 6.80 % |
| Insulation Level | LI 200 AC 85 / LI 75 AC 35 |
| Active Part Lifting Weight | 3750 kg |
| Oil Weight | 1650 kg |
| Total Weight | 7590 kg |
Applications
- Factory power distribution
- Residential power supply
- Construction temporary power
- Rural grid renovation
All ratings above are taken from the SZ20-3150/35 data sheet. For a different capacity, voltage ratio or vector group, send us the required rating and we will confirm the design and quotation.
