Designed with ONAN natural oil cooling system, it maintains stable temperature under 24-hour full-load continuous operation and handles short-time overload caused by peak loads and voltage fluctuations. Standard fitted with gas relay, pressure relief valve, temperature indicator and other safety parts, along with Class B insulation, it offers strong protection against short circuit, overheating and lightning strikes for maximum system safety.Direct factory pricing delivers excellent cost performance, and the sturdy structure guarantees a service life of 25–30 years. We also provide free pre-sales technical consultation, complete installation documents, remote troubleshooting and long-term spare parts supply, bringing worry-free after-sales service for your power projects.
1.Adopts high-grade grain-oriented cold-rolled silicon steel core, greatly reduces no-load loss & running power consumption, cuts long-term operation cost. Fully sealed corrugated tank isolates internal oil from air, slows insulation aging, maintenance-free in normal operation.
2.100% electrolytic copper windings with excellent conductivity and heat dissipation. Supports short-time overload under peak load; ONAN natural oil circulation cooling system ensures stable temperature rise even under continuous full load.
3.Class B insulation system, strong high voltage & lightning impulse withstand performance. Equipped with pressure relief valve, oil level gauge, temperature sensor, gas relay and explosion-proof device for overvoltage, overheat and short-circuit protection. IP54 outdoor weatherproof enclosure adapts to harsh outdoor conditions (-25℃ ~ +40℃ ambient temperature)
4.Optimized core lamination process minimizes vibration and running noise, meets international noise standard. Optional FR3 biodegradable insulating oil with high fire point, low flammability, environmentally friendly for green power projects.
5.Compact integrated structure, simple wiring and ground mounting. Widely used in power grid distribution, industrial plants, commercial buildings, residential communities, construction sites, solar/wind power station step-down systems. Compliant with IEC, ISO, CE, GB global certification standards.
6.Oil immersion effectively prevents windings from moisture, dust and corrosion. Long maintenance cycle (oil inspection every 1–3 years), robust welded steel tank anti-rust and anti-corrosion, service life up to 25+ years.
Technical Specifications of 250kVA Oil Immersed Power Transformer
Item
Parameter
Model
S11-M-250
Rated Capacity
250kVA
Phase
3 Phase
Cooling Method
ONAN Oil Natural Circulation
Insulation Class
Class B
Standard Compliance
IEC 60076, ISO 9001, CE, GB/T
High Voltage
6/10/11kV (Customizable)
Low Voltage
0.4kV (Customizable)
Vector Group
Dyn11 / Yyn0 Optional
Frequency
50Hz / 60Hz
Impedance Voltage
4% / 4.5%
Working Altitude
≤1000m
Ambient Temperature
-25℃ ~ +40℃
Why Choose Yiyue
Choosing Yiyue 250kVA three-phase oil immersed transformer means you get a reliable, energy-saving power distribution solution compliant with global electrical standards. Our unit uses full high-purity copper windings and low-loss silicon steel core in S11 energy-efficient design, effectively reducing power loss and daily operating costs. The fully sealed corrugated tank prevents oil oxidation and insulation aging, enabling nearly maintenance-free long-term running.
Packaging And Transportation
Yiyue Electric implements standardized packaging and shipping management to protect transformers, switchgears, cables and electrical components throughout the entire delivery process, ensuring products arrive in intact condition.
Medium & large equipment: Stretch film sealing for full moisture resistance, with foam padding on vulnerable parts for shock absorption
Heavy machinery & export shipments: ISPM15-compliant fumigated wooden cases secured with steel belts, suitable for long-distance international transit
All packages are marked with clear shipping marks and handling warnings for standard operation.
Production Lead Time
Standard in-stock items: 5–7 working days upon payment confirmation
Customized non-standard products: 7–15 working days after design confirmation & deposit
Large orders with special requirements: Lead time subject to separate confirmation
Shipping Method
Region
Estimated Transit Time
Remarks
Sea Freight
Southeast Asia
15–25 working days
Port to port, FCL & LCL available
Middle East
15–25 working days
Port to port, FCL & LCL available
North America
20–30 working days
Port to port, FCL & LCL available
Europe
25–35 working days
Port to port, FCL & LCL available
Oceania
20–30 working days
Port to port, FCL & LCL available
Africa
30–45 working days
Port to port, FCL & LCL available
Air Freight
Southeast Asia
5–7 working days
Airport to airport, for urgent orders
Middle East
5–7 working days
Airport to airport, for urgent orders
North America
10–15 working days
Airport to airport, for urgent orders
Europe
7–15 working days
Airport to airport, for urgent orders
Africa
4–6 working days
Airport to airport, for urgent orders
Air Freight (Express)
Worldwide Major Countries
3–7 working days
Door-to-door, suitable for small spare parts
Applications
FAQs
Is the S9 transformer suitable for new projects?
The S9 series is mainly recommended for replacement projects or markets with moderate energy-efficiency requirements.
Can the transformer be customized?
Yes. We support customization for voltage, capacity, dimensions, cooling methods, and special environmental adaptations. Our engineers will work with you to finalize the specs based on your project needs.
What standards do you follow?
We design and test to IEC 60076 and GB/T standards. For specific markets, we can also produce to ANSI, BS, DIN, or AS standards. Third-party inspections are welcome.
What about the production?
Production is done in our 8,000㎡ Hefei plant. Standard lead time is 20–35 working days, with expedited options available. Factory acceptance testing is welcome before shipment.
Through tailored consulting, reliable design, and a global service network, we ensure a
wonderful, long-term, and worry-free experience for business owners.
