1,000+ Electrical Transformers (7.2–34.5 kV, 25–3000 kVA) — UL Evaluated, Certificate of Compliance Available — In Stock & Ready to Ship from Houston, CA & Florida. Contact Us Today!
Primary Voltage Ratings: 23/35kV
Secondary Voltage Ratings: 13.8kV
CONNECTION TYPE: Delta-Wye configuration
Standards: IEEE
Application: Oil & gas
Power Rating: 12MVA & 16MVA & 20MVA
Certificate: UL
Cooling Method: ONAN / ONAF-1 / ONAF-2
Designed specifically for mobile power solutions in the oil and gas sector. The transformer is a custom engineered 3 phase distribution transformer combined with mobility, capacity, and rugged performance in one package. Daelim engineers has designed and developed this oil type transformer in accordance with IEEE C57.12.00 standards and has UL listed E583815. Featuring multiple cooling mechanisms to optimize the transformer working as per load requirements. Transformer also features an NLTC with a high voltage side having five tap positions and a single low voltage side giving transformer voltage range of 13.8 KV to 35 KV and power capacity of 12 MVA to 20 MVA.
The transformer is designed to operate for three different power ratings as per the electrical load requirements. This is especially necessary for the oil and gas field where work load depends on the nature of tasks being performed at the moment.
The transformer offers power rating of
Each power rating has its own specific voltage and current output. The 12 MVA here works as the baseline power rating and most transformer features like load losses and impedance are calculated on this base line.
The transformer is equipped with standard high voltage and low voltage winding. The high voltage winding gives different voltage options for each of the power ratings and thus has three different current ratings too.
Winding | Voltage | Configuration | Current |
HV | 23/25/27/33/35 kV | Wye (grounded) | 62.7 A (typical) |
LV | 13.8 kV | Delta | 3000 A |
The five voltage connection at high voltage winding enables the transformer to match the various grid conditions. This is an ideal feature of a transformer for mobile deployment across different regions.
| Type | Oil Type Distribution Transformer | Cooling Class | ONAN / ONAF / ONAF-2 |
| Tap Changer | No Load Tap Changer / Five Step | Manufacturing Standard | IEEE C57.12.00 |
| Phase | 3 Phase | UL Listed | E583815 |
| Power Rating | 12000 / 16000 / 20000 KVA at 55 C rise | Feet Altitude | 3282 feet |
| Base MVA | 12 MVA | Weight | 60540 pounds |
| Primary Voltage | 23,000 V GRDY / 13,280 V (line-to-neutral) | No load loss | 14.15 KW |
| Secondary Voltage | 480Y / 277 V | Rated load loss | 27.39 KW |
| Frequency | 60 Hz | Manufacturer | Daelim Transformers |
| High Voltage side | 23000 to 35000 V | First Manufactured in | Feb-25 |
| Low Voltage side | 13800 V | Application | Mobile Trailer Mount for oil and gas fields |
| Impedance | 5.33% | Vector Group | YNd1 (Delta-Wye configuration) |
| Core Construction | Core Type |
The transformer is featured with no load tap changer with five tap positions for high voltage winding to get five different combinations of electrical voltage and current for each power rating.
H (kVA) | |||||
Voltage (V) | Amps (12000 kVA) | Amps (16000 kVA) | Amps (20000 kVA) | Tap Position (POS.) | Connects |
35,000 | 197.9 | 284 | 329.9 | 1 | 1 – 2 |
33,000 | 210 | 279.9 | 349.9 | 2 | 2 – 3 |
27,000 | 256.6 | 342.2 | 427.7 | 3 | 3 – 4 |
25,000 | 277.1 | 369.5 | 481.9 | 4 | 4 – 5 |
23,000 | 301.2 | 401.6 | 502 | 5 | 5 – 6 |
X (kVA) | |||||
Voltage (V) | Amps (12000 kVA) | Amps (16000 kVA) | Amps (20000 kVA) | ||
13,800 | 502 | 689.4 | 836.7 | ||
The transformer is also featured with a strong thermal and electrical design with high current capabilities and stable voltage output. This ensures that the transformer is offering efficient energy conversion with low operational losses.
Parameter | Specification |
No-Load Losses | 14.15 kW |
Load Losses at 85°C | 27.59 kW |
Insulation Level | BIL 95 kV (Primary), with surge protection design compliance |
Temperature Rise | 65°C average (typical) |
The transformer is designed with three different cooling systems in one single package. The transformer has ONAN, ONAF 1, and ONAF 2 cooling systems and each system is designed to remove waste heat when the transformer is working at a specific load.
Cooling Method | Rated Capacity |
ONAN | 12 MVA |
ONAF-1 | 16 MVA |
ONAF-2 | 20 MVA |
The transformer is also equipped with a removable radiator to remove waste heat when the transformer is working at its maximum capacity. The transformer tank contains 1950 gallons of mineral oil at 25 degree centigrade for cooling and insulation purposes and also has a radiator that can contain 199 gallons of mineral oil at 25 degree centigrade. This cooling system is designed for the ambient operating temperature of 40 degree centigrade or 104 degree Fahrenheit.
Each part of the transformer is designed to have minimum weight without compromising quality so it can be installed on trailers and can be moved with ease. Weight of Transformer core, winding, tank and fittings, transformer oil and cooling system is mentioned below in pounds.
Component | Weight (lbs) / Volume |
Core and Coils | 33,730 lbs |
Tank and Fittings | 17,420 lbs |
Removable Radiators | 4,770 lbs |
Mineral Oil in Tank at 25°C | 1,950 gallons / 13,670 lbs |
Mineral Oil in Radiators at 25°C | 199 gallons / 1,500 lbs |
Total Weight | 68,350 lbs |
Weight of Transport (with oil) | 60,540 lbs |
Rise or Fall per 10°C Temperature Change | 0.76 in. |
The transformer was specifically designed to be trailer mounted transformer for a temporary and mobile power applications including
Each unit is designed for long term outdoor exposure and all types of dynamic load handling including transport resilience. This makes it ideal for oilfields, refineries, and for rapid deployment energy systems.
This transformer was not only designed and developed to meet specific criteria of electrical load but also was engineered to have specific features specially of dimensions to meet specific requirements.
This Transformer designed and developed by Daelim Transformers complies with all international standards and has all safety features.
At Daelim we offer a complete one stop solution of electrical transformer design, manufacturing, installation, and after sale service. Our team of engineers with decades of experience can design electrical transformers for your custom needs.
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