China Oil Immersed Transformer
China transformer manufacturer, Jinan Omek Electric Power Co., Ltd. (OMEK Power), is a global leader in the transformer industry. We have Indonesia branch and Assembly plants in Ethiopia. We are specializing in the production of oil filled transformers, dry type transformers, and related supporting products. All oil immersed transformers are manufactured in accordance with IEC standards.
With a strong focus on innovation, the company mainly produces S11, S13, and S20 series 11 kV, 20 kV, and 33 kV oil immersed power transformers, ensuring stable and reliable operation even in special applications and harsh environments.
Take an overview of our oil transformer:
Rated power: from 30 kVA to 10,000 kVA
Rated voltage: up to 35 kV (customizable)
Winding material: copper foil (if you need aluminium, we can also manufacture)
Standards and regulations: our oil type transformers meet IEC, CE, ASTA, etc.
OMEK™ Oil Type Transformer Ranges
Make a Choice on Sealing & Cooling Types
Hermetically Sealed Oil Immersed Transformer
This oil immersed transformer is specially designed with a fully sealed structure. It prevents the transformer oil from beding oxidized and evaporated due to air, dust, and rain. Very ideal for outdoor use.
The most convenient thing for you is, there is no need to constantly check the oil level. Basic maintenance is not required.
This hermetically sealed transformer is particularly ideal for distribution networks, buildings, industrial and mining areas, offshore platforms, as well as those damp and hot places with high maintenance-free requirements.
Open Type with Conservator
1. Key highlight – conservator design! It plays a role in oil pressure buffering and pressure balancing. You don’t need to inspect frequently.
2. Oil levels can be directly observed, and oil samples can be easily taken for offline testing such as dissolved gas analysis.
3. The conservator helps reduce noise and vibration, making it more suitable for noise-sensitive environments.
4. It is equipped with advanced safety protection devices. Thus, it can prevent electrical faults such as overloads and short circuits. Your safe and reliable operation is ensured!
5. Your will cost lower in initial procurement compared with hermetically sealed oil type transformers.
Typical applications: this type can be widely used in large substations, power plants, and critical load hubs.
Make A Choice by Installation
Ground mounted transformer/pad mounted transformer
– Easy ground installation. No piling or welding required
– The pad mounted type can reduce installation costs by over 30%
– Corrosion-resistant. Low maintenance.
Pole Mounted Transformers
This oil immersed transformer can be installed on the utility pole, with a typical capacity up to 500 kVA. It is cost-effective and adaptable to harsh environments.
This pole mounted transformer oil filling is widely used in rural grids, utilities and street lighting systems.
Package and Unit Substations
Compact design. They have integrated HV, LV, and transformer units. Their steel enclosures are moisture-proof and fire-resistant. You can have easy transport and fast installation.
This oil filled station type transformer is also suitable for solar power station, EV charging, public and temporary projects.
Amorphous oil transformer
Its key highlight: Amorphous alloy core design! 70–80% lower core losses, compared to silicon steel transformers.
This amorphous transformer has ultra-low no-load loss and reduced noise. More importantly, it is energy-saving and environmentally friendly.
OMEK Oil Immersed Transformer Specification
Phase | Cooling type | Insulation class | Designed life expectancy |
Single phase (10-160kVA) Three phase (30-4000kVA） | self cooled, water cooled | A/H | 30 years |
We can also provide you with customized product solutions. Features such as alarms and monitoring devices can be optionally installed. If you have any specific requirements, circuit breakers can be directly integrated into the system as well.
- S11: 10kV
- S11: 20kV
- S13: 10kV
S11-M-(30-2500)/10
S11-M-(30-2500)/10 3 phase Oil-immersed distribution transformer
| Rated capacity(kVA) | Voltage combination | Connected group label | No-load loss (W) | Load loss (75°C)(W) | No-load current (%) | Impe-dance voltage（%） | Overall dimension(L×w×h) | Total weight (kg) | ||
| High voltage (kV) | Tap range | Low Voltage (kV) | ||||||||
| 30 | 6 6.3 6.6 10 10.5 11 | ±2×2.5 ±5 | 0.4 | Dyn11 Yyn0 Yzn11 | 100 | 630/600 | 1.5 | 4 | 740×610×830 | 300 |
| 50 | 130 | 910/870 | 1.3 | 770×760×860 | 375 | |||||
| 63 | 150 | 1090/1040 | 1.2 | 800×740×890 | 425 | |||||
| 80 | 180 | 1310/1250 | 1.2 | 800×760×920 | 455 | |||||
| 100 | 200 | 1580/1500 | 1.1 | 830×780×950 | 530 | |||||
| 125 | 240 | 1890/1800 | 1.1 | 830×820×1020 | 590 | |||||
| 160 | 280 | 2310/2200 | 1 | 860×790×1060 | 685 | |||||
| 200 | 340 | 2730/2600 | 1 | 890×860×1070 | 780 | |||||
| 250 | 400 | 3200/3050 | 0.9 | 920×950×1090 | 895 | |||||
| 315 | 480 | 3830/3650 | 0.9 | 1290×880×1120 | 1070 | |||||
| 400 | 570 | 4520/4300 | 0.8 | 1370×930×1140 | 1295 | |||||
| 500 | 680 | 5410/5150 | 0.8 | 1370×940×1190 | 1430 | |||||
| 630 | Dyn11 Yyn0 Yzn11 | 810 | 6200 | 0.6 | 4.5 | 1460×990×1240 | 1720 | |||
| 800 | 980 | 7500 | 0.6 | 1570×1090×1280 | 1985 | |||||
| 1000 | 1150 | 10300 | 0.6 | 1720×1260×1340 | 2255 | |||||
| 1250 | 1360 | 12000 | 0.5 | 1660×1180×1430 | 2785 | |||||
| 1600 | 1640 | 14500 | 0.5 | 1760×1210×1480 | 3380 | |||||
| 2000 | 1940 | 18300 | 0.4 | 5 | 1930×1360×1490 | 4060 | ||||
| 2500 | 2290 | 21200 | 0.4 | 2080×1360×1570 | 5105 | |||||
S11-M-(30-2500)/20
S11-M-(30-2500)/20 3 phase oil-immersed distribution transformer
| Rated capacity(kVA) | Voltage combination | Connected group label | No-load loss (W) | Load loss (75°C)(W) | No-load current (%) | Impe-dance voltage（%） | ||
| High voltage (kV) | Tap range | Low Voltage (kV) | ||||||
| 30 | 20 | ±2×2.5 ±5 | 0.4 | Dyn11 Yzn11 Yyn0 | 100 | 690/660 | 0.3 | 5.5 |
| 50 | 130 | 1010/960 | 0.24 | |||||
| 63 | 150 | 1200/1150 | 0.23 | |||||
| 80 | 180 | 1440/1370 | 0.22 | |||||
| 100 | 200 | 1730/1650 | 0.21 | |||||
| 125 | 240 | 2080/1980 | 0.2 | |||||
| 160 | 290 | 2540/2420 | 0.19 | |||||
| 200 | 340 | 3000/2860 | 0.18 | |||||
| 250 | 400 | 3520/3350 | 0.17 | |||||
| 315 | 480 | 4210/4010 | 0.16 | |||||
| 400 | 570 | 4970/4730 | 0.16 | |||||
| 500 | 680 | 5940/5660 | 0.16 | |||||
| 630 | Dyn11 Yyn0 | 810 | 6820 | 0.15 | 6 | |||
| 800 | 980 | 8250 | 0.15 | |||||
| 1000 | 1150 | 11300 | 0.14 | |||||
| 1250 | 1380 | 13200 | 0.13 | |||||
| 1600 | 1660 | 16000 | 0.12 | |||||
| 2000 | 1950 | 19100 | 0.11 | |||||
| 2500 | 2340 | 22200 | 0.11 | |||||
S13-M-(30-2500)/10
S13-M-(30-2500)/10 3 phase Oil-immersed distribution transformer
| Rated capacity(kVA) | Voltage combination | Connected group label | No-load loss (W) | Load loss (75°C)(W) | No-load current (%) | Impe-dance voltage（%） | Overall dimension(L×w×h) | Total weight (kg) | ||
| High voltage (kV) | Tap range | Low Voltage (kV) | ||||||||
| 30 | 6 6.3 6.6 10 10.5 11 | ±2×2.5 ±5 | 0.4 | Dyn11 Yyn0 Yzn11 | 80 | 630/600 | 1.5 | 4 | 740×610×830 | 300 |
| 50 | 100 | 910/870 | 1.3 | 770 × 760 x 860 | 375 | |||||
| 63 | 110 | 1090/1040 | 1.2 | 800×740×890 | 425 | |||||
| 80 | 130 | 1310/1250 | 1.2 | 800×760×920 | 455 | |||||
| 100 | 150 | 1580/1500 | 1.1 | 830×780×950 | 530 | |||||
| 125 | 170 | 1890/1800 | 1.1 | 830×820×1020 | 590 | |||||
| 160 | 200 | 2310/2200 | 1 | 860×790×1060 | 685 | |||||
| 200 | 240 | 2730/2600 | 1 | 890×860×1070 | 780 | |||||
| 250 | 290 | 3200/3050 | 0.9 | 920×950×1090 | 895 | |||||
| 315 | 340 | 3830/3650 | 0.9 | 1290×880×1120 | 1070 | |||||
| 400 | 410 | 4520/4300 | 0.8 | 1370×930×1140 | 1295 | |||||
| 500 | 480 | 5410/5150 | 0.8 | 1370×940×1190 | 1430 | |||||
| 630 | Dyn11 Yyn0 Yzn11 | 570 | 6200 | 0.6 | 4.5 | 1460×990×1240 | 1720 | |||
| 800 | 700 | 7500 | 0.6 | 1570×1090×1280 | 1985 | |||||
| 1000 | 830 | 10300 | 0.6 | 1720×1260×1340 | 2255 | |||||
| 1250 | 970 | 12000 | 0.5 | 1660×1180×1430 | 2785 | |||||
| 1600 | 1170 | 14500 | 0.5 | 1760×1210×1480 | 3380 | |||||
| 2000 | 1360 | 18300 | 0.4 | 5 | 1930×1360×1490 | 4060 | ||||
| 2500 | 1600 | 21200 | 0.4 | 2080×1360×1570 | 5105 | |||||
Oil Immersed Transformer Features
We adopt advanced insulation material from DuPont of the United States.
It meets China Grade 1 Energy Efficiency and EU Ecodesign requirements.
Our mineral oil transformers are comply with fire safety codes IEC 60076-11.
OMEK’s oil immersed transformers’ service life is designed with a long life span, above 30 years.
The sealed designs can isolate oxygen and moisture. Very suitable for harsh outdoor environments.
It is more adaptable for large voltage design, and the most common type as the substation transformer.
Our Oil Immersed Transformers Components
Below are some of accessories of our oil type transformer. For more requires, you can move to our transformer accessories page for more details.
Our Factory
Our Core Technology - Triangular 3D Coiled Iron Core
This is our core upgraded technology! We have moved away from the old flat iron core and adopted the 3D coil structure.
We adopts this advanced technology into the oil immersed transformers manufacturing. This ensures symmetrical three-phase magnetic paths and uniform magnetic fields.
The benefits are real and substantial: energy consumption has decreased, no-load losses have reduced, no-load current has decreased, the ability to withstand short circuits has become more reliable, and the operating noise has been lowered by 8-9 decibels. It’s both cost-effective and quiet to use!
Are you looking for a reliable oil immersed transformer manufacturer?
Don’t hesitate to get in touch with us! Before placing an order, feel free to let us know your specific parameters, such as dimensions, materials, and models. Custom designs based on customer drawings are welcome!
Our Strict Oil Filled Transformer Testings
For every oil-immersed transformer we manufacture at OMEK, the performance tests must be conducted before leaving the factory! This ensures all parameters of each unit meet the standards. Thus, the safety and reliability of the transformers are firmly guaranteed from the very beginning.
Certified and Authoritative Oil Filled Transformer
- – ISO 9001, ISO 14001, ISO 45001, OHSAS 18001, CCC Certification, AAA Credit Rating Certification and IEC60076 standards.
- – Twelve oil filled transformer models, including three-phase oil immersed off-load tap changing distribution transformers such as S20-M-30 ~ 125/10-NX2 (10/0.4 kV) and SBH21-M-2000 ~ 2500/10-NX2 (10/0.4 kV), have been awarded the PCCC Energy-Saving Product Certification.
- – The oil immersed amorphous alloy distribution transformer SBH-M-400/10-NX1 (Grade 1 energy efficiency) has been selected for the National Recommended Catalog of Industrial Energy-Saving Technologies and Equipment.
- – Holder of 50 utility model patents.
- – Recently participated in oil immersed transformer tenders organized by power companies in seven provinces across China, with a total of 973 units supplied, receiving highly positive feedback.
- – Each batch of oil filled transformers is delivered with a complete set of type test reports and factory acceptance test reports.
Our Oil Filled Transformer Projects
Foreign Client On-site Visit
Southern Power Grid Tender Project - Delivered
China Hydraulic Project Transformer - - Installed & Tested
Transformers for Indian Railway Infrastructure - Shipped
Port Grid Upgrade in Chile - Shipped
Desalination Plant in UAE - Installed
Copper Mine Project in Zambia - Delivered
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FAQ
Have any questions? We’re here to help you out.
The oil used in transformers is neither gasoline nor diesel. It is specially refined mineral oil or synthetic oil designed for electrical equipment.
Transformer oil must provide high insulation strength, appropriate viscosity, and a high flash point. Why? Because it needs to ensure electrical insulation and stable operation while minimizing fire risk.
If oil test results show increased moisture content or a higher acid value, it’s time to replace the transformer oil.
Commonly used transformer insulating oils include No. 10 oil, No. 25 oil, No. 45 oil, and Karamay oil. These are all mineral oils refined from petroleum and have a clear appearance.
– No. 25 oil is suitable for cold areas around -25 °C
– No. 45 oil is suitable for colder areas around -45 °C
In warmer regions, oil No. 25 is usually used. But in colder regions, No. 45 oil is preferred. There is also vegetable-based transformer oil, which represents a higher-grade option with better cooling performance, stronger insulation, and higher temperature resistance, although it comes at a higher cost.
Actually, it’s mainly for two purposes – insulation and cooling. The insulating ability of transformer oil is much stronger than that of air. It can firmly prevent internal current short circuits and avoid problems.
Moreover, when the transformer is working, it will get hot. With the circulation of the oil, the heat can be removed, preventing it from breaking down due to overheating.
Additionally, it can reduce local discharge, prevent parts from oxidizing and getting dirty, and keep the interior clean. From this perspective, filling the transformer with oil is extremely important for its normal operation and allowing it to last for many more years!
When the transformer is newly manufactured, the oil tank is filled with protective gases such as nitrogen. The first step before installation is to use a vacuum unit to completely evacuate the gases from the tank. Once the vacuum level is met, the vacuum oil filling process can begin.
During the oil filling process, the insulating oil is pumped into the tank from the bottom. However, during this process, water and air and other impurities are inevitably mixed into the oil – some are inherent in the oil itself, and some are accidentally introduced during the oil filling process.
At this point, the oil filter machine comes into play! The oil needs to undergo a hot oil circulation purification process: the oil in the transformer is pumped into the oil filter machine, and solid impurities are filtered out layer by layer first, then heated to remove moisture and gases, and the purified oil is then returned to the transformer. After this process is completed once, the quality of the oil is guaranteed.
A reminder: During actual construction, for different models of transformers and different oil filter machines, the corresponding operation specifications are also different. They must be carried out according to the requirements.
This article Hermetically Sealed vs Conservator Type Transformers: 7 Differences You Can’t Ignore will help you a lot.