The Redway Electric 50kVA three phase oil immersed transformer is a compact, energy-efficient distribution transformer designed for 10kV medium-voltage networks stepping down to 0.4kV low-voltage output. Manufactured at our 20,000 m² Shijiazhuang production facility to IEC 60076-1 standard, this unit is engineered for reliable continuous service in outdoor pole-mounted, pad-mounted, and ground-level substation installations worldwide.
This 50kVA three phase oil immersed transformer is available in S11 and S13 loss grades, with copper or aluminum winding options, Dyn11 or Yyn0 vector group, and a standard DETC tap changer of ±2×2.5%. Every unit undergoes a full factory routine test before shipment and is shipped with a signed test report.
Customizable voltage and capacity according to requirements.
| Maximum Load Loss and Maximum No-Load Loss of Transformers with a Rated Frequency of 50 Hz |
| |
Grade 1 |
Grade 2 |
| Rated Power |
Maximum Load Loss |
Maximum No-load Loss |
Maximum Load Loss |
Maximum no-load loss |
| kVA |
(Unit: inch) |
(Unit: inch) |
(Unit: inch) |
(Unit: inch) |
| ≤25 |
900 |
70 |
600 |
63 |
| 50 |
1100 |
90 |
750 |
81 |
| 100 |
1750 |
145 |
1250 |
130 |
| 160 |
2350 |
210 |
1750 |
189 |
| 250 |
3250 |
300 |
2350 |
270 |
| 315 |
3900 |
360 |
2800 |
324 |
| 400 |
4600 |
430 |
3250 |
387 |
| 500 |
5500 |
510 |
3900 |
459 |
| 630 |
6500 |
600 |
4600 |
540 |
| 800 |
8400 |
650 |
6000 |
585 |
| 1000 |
10500 |
770 |
7600 |
693 |
| 1250 |
11000 |
950 |
9500 |
855 |
| 1600 |
14000 |
1200 |
12000 |
1080 |
| 2000 |
18000 |
1450 |
15000 |
1305 |
| 2500 |
22000 |
1750 |
18500 |
1575 |
| 3150 |
27500 |
2200 |
23000 |
1980 |
| Note: In some countries, relevant regulations permit higher loss values for transformers that fall outside the applicable scope of this table (such as transformers with wider tap ranges, dual low-voltage windings, or higher voltage levels). |
Factory Testing — What Every Unit Goes Through Before Shipment
Redway Electric applies a mandatory routine test protocol to every 50kVA three phase oil immersed transformerleaving our Shijiazhuang facility, fully aligned with IEC 60076-1 Clause 10 requirements:
Routine Tests (Every Unit):
| Test |
Standard Reference |
Acceptance Criterion |
| Winding resistance (all taps) |
IEC 60076-1 §10.2 |
Within ±0.5% of calculated design value |
| Voltage ratio measurement |
IEC 60076-1 §10.3 |
Within ±0.5% of rated ratio |
| Phase displacement verification |
IEC 60076-1 §10.3 |
Dyn11 / Yyn0 confirmed |
| No-load loss & no-load current |
IEC 60076-1 §10.4 |
≤125W (S11) / ≤95W (S13) |
| Load loss & short-circuit impedance |
IEC 60076-1 §10.5 |
Within ±10% of specified values |
| Induced voltage test |
IEC 60076-3 §12.3 |
2× rated voltage, 60 seconds, no breakdown |
| Separate source withstand (HV) |
IEC 60076-3 §12.2 |
35kV AC, 60 seconds, no breakdown |
| Insulation resistance |
Megger measurement |
≥1,000 MΩ (20°C reference) |
| Oil leakage pressure test |
Factory protocol |
Zero leakage at 0.05 MPa overpressure |
Type Tests (Available on Request): Temperature rise test (IEC 60076-2), lightning impulse withstand test (IEC 60076-3), short-circuit withstand test (IEC 60076-5), and acoustic sound level measurement (IEC 60076-10) can be arranged with independent third-party witnesses (SGS, Bureau Veritas, TÜV Rheinland) upon customer request.
Full test report documentation is issued with every shipment and available in electronic format (PDF) within 24 hours of test completion.
Typical Applications for the 50kVA Rating
The 50kVA three phase oil immersed transformer sits at the lower end of three-phase distribution transformer ratings, making it the standard choice for applications requiring reliable 10kV-to-0.4kV step-down at lower load densities:
Rural and Agricultural Electrification The 50kVA rating is the most widely used size for village-level distribution points in rural electrification programs across Africa, South and Southeast Asia, and Latin America — where connected loads are limited to lighting, small appliances, water pumping, and light commercial use. Pole-mounted installation on existing 10kV overhead lines makes this the lowest-cost infrastructure option for extending grid access to dispersed communities.
Small Commercial Buildings and Light Industrial Units Small workshops, petrol stations, small hotel premises, school buildings, health centres, and similar facilities with installed capacities in the 30–50kW range (30–40kVA at 0.8 pf) are ideally served by a 50kVA three phase oil immersed transformer with minimal capacity reserve.
Construction Site Temporary Power Supply Temporary 10kV distribution for construction sites needing three-phase LV supply for tools, lighting, and small equipment, where a compact pole-mounted unit is the most cost-effective approach and the transformer will be relocated after project completion.
Solar PV and Wind Micro-Generation Collection Points Small-scale renewable energy installations (solar PV up to ~35kWp) requiring a grid-tie step-up point from inverter output (typically 0.3–0.4kV) to the local 10kV collection network.
Standby and Emergency Grid Backup Substations Secondary distribution supply points in ring-feed or meshed distribution networks where a small-capacity normally-open point transformer provides contingency supply paths during primary source outages.
Request a Factory
Submit your project requirements and we'll respond within 24 hours with a complete technical confirmation and factory-direct pricing for your 50kVA three phase oil immersed transformer order.
To get the most accurate quotation, please provide:
- Quantity required
- Primary voltage (if different from 10kV)
- Secondary voltage (if different from 0.4kV)
- Grid frequency (50Hz or 60Hz)
- Installation type (pole-mounted / pad-mounted / indoor)
- Applicable standard (IEC / IEEE / local grid code)
- Delivery destination and required Incoterms
- Any special environment conditions (altitude, temperature, corrosive atmosphere)
