Product advantages
Key Advantages of 35kV Three-Phase Oil-Immersed Transformer
Leading-Edge Winding Technology
High-purity oxygen-free copper conductor is adopted for windings. Winding structure is optimized via electromagnetic simulation to reduce partial discharge and hot spots. Automatic winding equipment ensures consistent tightness, which effectively improves the overload capability and service life of the transformer.
Superior Mechanical Strength & Short-circuit Withstand
The whole winding is fixed by high-strength insulating support. The structural layout is verified by short-circuit simulation test. It can withstand sudden short-circuit impact without permanent deformation, greatly reducing failure risks in harsh grid conditions.
Advanced Step-Lap Core Structure
High permeability cold-rolled grain-oriented silicon steel sheet is used for the iron core with step-lap joint design. This structure minimizes magnetic flux leakage and no-load loss, helping end users save long-term electricity operation cost.
Precision-Engineered Tank & Enclosure
The transformer tank is fabricated by robotic automatic welding and inspected by leak detection. Excellent oil tightness avoids oil leakage trouble on site. Optional surface anti-rust and salt-spray resistant coating is available for coastal and high-humidity areas.
High-Efficiency Cooling System
Standard cooling mode is ONAN (Oil Natural Air Natural). ONAF cooling option can be supplied for larger capacity or high ambient temperature environment, which improves heat dissipation capacity and guarantees stable output under continuous load.
Top-Tier Raw Materials & Components
Main accessories including conservator, oil level indicator, bushing, pressure relief valve and temperature gauge are supplied by qualified reliable vendors. All materials pass incoming inspection to guarantee the overall reliability of the complete unit.
Technical Configurations & Safety Standards
All units are manufactured and tested following IEC 60076 series standards. We can carry out routine test, type test and special witness test as required by buyers. Optional tap changer types: off-circuit tap changer (NLTC) and on-load tap changer (OLTC). Common vector group: Dyn11, Yyn0, YNd11. Altitude adaptation: standard for ≤1000m; high-altitude version for 1000m~3000m customized. Ambient temperature: -40℃ ~ +40℃, tropical version optional.
Application Scenarios
* Urban and rural 35kV power distribution network
* Mining, chemical and heavy industrial power supply
* Ground-mounted solar photovoltaic power stations
* Onshore wind farm step-up system
* Commercial complex and large industrial park
* Overseas EPC power transmission & distribution projects
* Remote area independent power supply system
Quality Control and Testing
Inspection and testing requirements should be defined according to the applicable standards, approved technical specifications, and purchase contract. Relevant routine test records and supporting technical documents can be provided as agreed for the project.
Where required, customers may specify additional inspection, factory acceptance testing, or third-party witnessing arrangements in advance.
Project Cases
We have supplied 35kV oil immersed distribution transformers for multiple overseas grid and new energy projects. Our engineering team supports full technical coordination, drawing approval, factory inspection, shipment tracking and after-sales technical guidance.
We can provide reference project photos, test reports and customer reference letters upon inquiry.
35kV Three-Phase Oil-Immersed Power Distribution Transformer FAQ
What international standards do your 35kV transformers comply with?
Our products are strictly designed and tested per IEC 60076, IEC 60296 and IEC 60085. We also comply with GB, EN, GOST, ANSI/IEEE, AS/NZS, INMETRO, SABS, KEBS, SASO and other regional grid standards.
Can you customize the secondary voltage and vector group?
Yes. Secondary voltage, vector group, tap range and accessories can be fully customized to match your local grid design. Please send your single-line diagram for technical quotation.
What is the difference between ONAN and ONAF cooling?
ONAN means oil natural air natural without cooling fans, for normal load condition. ONAF adopts cooling fans, which can increase the overload capacity, suitable for high temperature environment or continuous heavy load.
Do you support witness test at factory?
Yes. We accept third-party or buyer witness test including ratio test, resistance test, no-load & load loss test, dielectric test and partial discharge test. Test reports will be provided after testing.
What is your lead time for 35kV oil immersed transformer?
Standard models normally take 25–40 working days. For special customized parameters or OLTC type transformers, lead time will be confirmed after drawing confirmation.
What package do you use for export shipment?
Standard export plywood fumigation-free wooden case or steel frame packing. Anti-rust treatment and oil filling are finished before delivery, suitable for sea freight and long-distance transportation.
Can you provide technical datasheet and CAD drawing?
Yes. After receiving your inquiry, our technical team will prepare datasheet, general arrangement drawing and wiring drawing for your engineering review.
What is the warranty period?
We provide 12 months warranty after shipment or 18 months from factory delivery, whichever comes first. We supply lifetime technical support and spare parts supply.
Is copper winding optional or standard?
Oxygen-free copper winding is our standard configuration. Aluminum winding version can be supplied if specially requested for cost budget consideration.
Can it work in coastal salt fog environment?
Yes. We can apply multi-layer salt-spray resistant paint for coastal areas, and recommend sealing accessories to slow down corrosion. Please advise site environment condition when inquiry.
Product parameters
Customization Options
Transformer specifications can be reviewed against the customer's project requirements, including:
- Rated primary and secondary voltages
- Rated capacity and operating frequency
- Winding material and vector group
- No-load and load-loss requirements
- Tap-changing range and method
- Tank configuration and protective accessories
- Ambient temperature, altitude, and installation conditions
Final configuration and availability should be confirmed in the technical proposal.
Selection Table
- Input voltage: 35kV
- Output voltage: 0.4kV
- Capacity: 50-5000 kva
- Frequency: 50HZ/60HZ
- Voltage regulation mode: NLTC (no Load tap changer)
- Remark: voltage, capacity, frequency, connection group and loss can be customized according to customer requirements
| 额定容量Capacity |
额定电压及分接范围Rated voltage&Off-load tapping |
联结组标号
Vector
GroupSymbol |
空载损耗
NO-load
loss（W） |
负载损耗
Load loss（W） |
空载电流
NO-load current |
短路阻抗Short
circuit impedance(%) |
高压
H.V(kv) |
高压分接范围
High pressure
Tap range（%） |
低压
L.V(kv) |
| 50 kva |
33kV
35kV
38.5kV |
±5%
±2x2.5% |
0.4 |
Dyn11
Yyn0 |
210 |
1270/1210 |
2.0 |
6.5 |
| 100 kva |
290 |
2120/2020 |
1.8 |
6.5 |
| 125 kva |
340 |
2500/2380 |
1.7 |
6.5 |
| 160 kva |
360 |
2970/2380 |
1.6 |
6.5 |
| 200 kva |
430 |
3500/3330 |
1.5 |
6.5 |
| 250 kva |
510 |
4160/3960 |
1.4 |
6.5 |
| 315 kva |
610 |
5010/4770 |
1.4 |
6.5 |
| 400 kva |
730 |
5050/5760 |
1.3 |
6.5 |
| 500 kva |
860 |
7280/6930 |
1.2 |
6.5 |
| 630 kva |
1040 |
8280 |
1.1 |
6.5 |
| 800 kva |
1230 |
9900 |
1.0 |
6.5 |
| 1000 kva |
1440 |
12150 |
1.0 |
6.5 |
| 1250 kva |
1760 |
14670 |
0.9 |
6.5 |
| 1600 kva |
2120 |
17550 |
0.8 |
6.5 |
| 2000 kva |
2490 |
20740 |
0.8 |
6.5 |
| 2500 kva |
2950 |
24420 |
0.8 |
6.5 |
| 3150 kva |
3510 |
29050 |
0.7 |
6.5 |
| 4000 kva |
4200 |
34940 |
0.7 |
6.5 |
| 5000 kva |
4960 |
41160 |
0.7 |
6.5
|
Ordering instructions
Ordering Instructions
To provide accurate quotation and technical drawing, kindly offer below information when sending inquiry:
1.Rated capacity
2.Primary voltage & secondary voltage
3.Tap changer type: NLTC or OLTC
4.Frequency: 50Hz or 60Hz
5.Vector group requirement
6.Site altitude, ambient temperature and environment (coastal / dusty / tropical)
7.Required standards and certification documents
8.Quantity and target delivery time
Contact Us
Send your technical requirement to get competitive factory price and detailed proposal. We support project-oriented technical communication and long-term distributor cooperation.
