66/69 kV Oil-Immersed Power Transformer
Rated voltage: 66 / 69 kV Rated capacity: 6,300 kVA – 63 MVA Application scenarios: Substations, photovoltaic power plants, steel mills, airports, ports, and other utility & industrial installations. Certifications & Standards: EC, GB, ANSI……
Rated voltage: 66 / 69 kV
Rated capacity: 6,300 kVA – 63 MVA
Application scenarios: Substations, photovoltaic power plants, steel mills, airports, ports, and other utility & industrial installations.
Certifications & Standards: EC, GB, ANSI/IEEE, NEMA
Overview
In today’s global grid environment, reliable and efficient voltage transformation is critical. Our 66/69 kV oil-immersed power transformer from ZTelec Electric is engineered for high-voltage transmission, industrial substations, and demanding utility applications. With a compact footprint, excellent weather resistance, and cost-effective lifecycle performance, it is ideal for power systems, industrial/mining enterprises, transportation infrastructure, telecom hubs, and research institutions.
Featuring advanced core and coil technologies — including grain-oriented silicon steel and high-quality copper windings — this transformer delivers low losses, high mechanical strength, and reliable long-term performance under heavy duty cycles.
Features & Benefits
High efficiency & low losses
Optimised core geometry and winding arrangements reduce no-load and stray losses for superior energy performance and lower operating costs.
Robust construction
Steel oil tank with corrosion-resistant treatment; available in corrugated or expanding radiator designs to match site cooling and footprint requirements.
Excellent insulation & dielectric strength
Designed and tested for harsh environmental conditions, offering durable insulation systems to ensure long service life and reliable operation.
Versatile applications
Suited for grid step-up/step-down, power plants, industrial substations, transportation networks, telecom power supplies, and research/test laboratories.
Customisable to standards
Designed for voltage levels up to 69 kV with multiple capacity options and factory customization to meet client specifications and local standards.
Product Series & Specifications
Double-Winding Off-Circuit Tap-Changer (NLTC) – 66 kV Class
| Rated Capacity (kVA) | Typical Voltage Ratio (kV) | Vector Group | Impedance Voltage (%) | Reference Size L×W×H (mm) | No-Load Loss (W) | Load Loss (W) |
|---|---|---|---|---|---|---|
| (SF11) 6,300/66 | 9 | 4800×3900×4000 | 7,300 | 34,200 | ||
| (SF11)8,000/66 | – | 22 | 4900×4100×4200 | 8,900 | 40,500 | |
| (SF11)10,000/66 | – | 25 | 5000×4300×4400 | 10,500 | 47,800 | |
| (SF11)12,500/66 | – | 28 | 5100×4400×4500 | 12,400 | 56,800 | |
| (SF11)16,000/66 | – | 30 | 5200×4600×4600 | 15,000 | 69,800 | |
| (SF11)20,000/66 | HV: 66/69 KV ±2×2.5% LV: 3.15, 3.3, 6.3, 6.6, 10.5 kV | YNd11 | 34 | 5300×4700×4800 | 17,600 | 84,600 |
| (SF11)25,000/66 | – | 41 | 5500×4700×5000 | 20,800 | 100,000 | |
| (SF11)31,500/66 | – | 46 | 5600×4800×5200 | 24,600 | 120,000 | |
| (SF11)40,000/66 | – | 57 | 5800×5000×5300 | 29,400 | 141,000 | |
| (SF11)50,000/66 | – | 67 | 6000×5300×5500 | 35,200 | 167,000 | |
| (SF11)63,000/66 | – | 73 | 6200×5600×5700 | 41,600 | 198,000 |
Double-Winding On-Load Tap-Changer (OLTC) – 66 kV Class
| Rated Capacity (kVA) | Typical Voltage Ratio (kV) | Vector Group | Impedance Voltage (%) | Reference Size L×W×H (mm) | No-Load Loss (W) | Load Loss (W) |
|---|---|---|---|---|---|---|
| (SFZ11)6,300/66 | 9–11 | 5600×3800×4000 | 8,000 | 34,200 | ||
| (SFZ11)8,000/66 | – | – | 22 | 5700×4000×4200 | 9,600 | 40,500 |
| (SFZ11)10,000/66 | – | – | 27 | 5800×4200×4400 | 11,300 | 47,800 |
| (SFZ11)12,500/66 | – | – | 30 | 5900×4300×4500 | 13,400 | 56,800 |
| (SFZ11)16,000/66 | HV: 66/69 KV ±2×2.5% → LV: 3.15, 3.3, 6.3, 6.6, 10.5 kV | YNd11 | 33 | 6000×4400×4600 | 16,100 | 69,800 |
| (SFZ11)20,000/66 | – | – | 36 | 6100×4500×4800 | 19,200 | 84,600 |
| (SFZ11)25,000/66 | – | – | 43 | 6500×4500×5000 | 22,700 | 100,000 |
| (SFZ11)31,500/66 | – | – | 49 | 6600×4600×5200 | 26,900 | 120,000 |
| (SFZ11)40,000/66 | – | – | 59 | 6800×4800×5300 | 32,200 | 141,000 |
| (SFZ11)50,000/66 | – | – | 69 | 7000×5000×5500 | 38,000 | 167,000 |
| (SFZ11)63,000/66 | – | – | 75 | 7400×5300×5700 | 44,900 | 198,000 |
Typical Applications
Transmission substations and grid step-up/step-down for 66/69 kV systems.
Industrial plants and mining operations that require reliable high-voltage transformation.
Utility and public infrastructure installations such as rail, telecom, airports, and ports.
Research, education, and test facilities for power system laboratories.
Why Choose Our 66/69 kV Transformer?
Global industry-proven designs backed by decades of service in power and utility sectors, offering extensive project references and field experience.
Flexible specification options covering a wide capacity range from 6,300 kVA to 63,000 kVA, with site-specific adaptations (altitude, temperature, cooling type).
Customisable features including tap-changer options, vector groups, and mechanical/access configurations to match installation and operation needs.
Comprehensive technical support including full documentation, factory and site acceptance testing, transport logistics, and on-site commissioning assistance.
Ordering Information
When placing an order, please specify the rated capacity, voltage ratio (HV & LV), vector group, cooling type, and whether an OLTC (on-load tap-changer) or NLTC (off-circuit tap-changer) is required. For site conditions that exceed standard service limits (altitude above 1,000 m or ambient temperature outside −45 °C to +40 °C), inform our engineering team for bespoke design adjustments.
Our team supports site-specific drawings, transport planning, installation guidance, and commissioning support to ensure on-time and on-spec delivery.
Contact ZTelec Electric for detailed specifications, drawing packages, and a tailored proposal for your 66/69 kV transformer project.
