230 kV 220kv Power Transformer

  • Primary Voltage Ratings: 220 kV, 230 kV or others
  • Secondary Voltage Ratings: 69/35/37/34.5/26.4./11/10.5/6.6/13.2 kV or others
  • H.V. TAP RANGE: ±8×1.25% or others
  • CONNECTION TYPE: YNd11 or others
  • TYPE: Oil immersed
  • BIL: up to 900 kV
  • Standards: IEEE, CSA, IEC
  • Application: Substation, transmison line
  • Power Rating: 10MVA, 12.5MVA, 15MVA, 18MVA, 20MVA, 25MVA

Daelim 220kV 230 kV transformers are according to international standard1. GB 6451 Specification and technical requirements for oil-immersed power transformers;2. IEC 60076 Power Transformers;3. AS NZS 60076 Power Transformers;4.CSAC88-16 Power Transformers;5. ANSI/IEEE C57.12.00 IEEE Standard for General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers;6. GOST R 52719 Power Transformers - General Specifications; 7. EN60076 Power Transformes8. Local After-Sales Services In North America South America and other regions respond to your needs within 24 hours. etc, the power ratings are up to 270 MVA, and for voltages up to the highest insulation class of 900 kV.

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230 kV Transformer Specifications
Phase 3 phase Std.  IEEE
Cooling means KNAN/KNAF/KNAF Fluid Vegetable Oil
Power KNAN 10MVA Frequency 60Hz
Power KNAF1 12.5MVA HV bushing  Porcelain
Power KNAF2 15MVA LV bushing Porcelain
Type Oil Immersed with oil pillow Environmental condition Outdoor
HV Voltage 230 kV Paint Color Grey 70
LV Voltage 26.4x13.2 kV Winding Material  Copper
Environmental conditions -25°C to 35°C Vector group Dyn1

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Daelim Transformer

230 kV Transformer

The S-10/12.5/15-230/26.4(13.2) stands as a meticulously crafted HV transformer from Daelim Transformer. It with a primary voltage of 230 kV and a secondary voltage of 26.4/13.2 kV, offering power ratings of 10 MVA, 12.5 MVA, and 15 MVA. This 230 kV power transformer application in Nevada, USA, plays a pivotal role in enhancing power transmission within the region, exemplifying Daelim Transformer's commitment to sustainable power solutions.

Distinguished by its KNAN/KNAF/KNAF cooling system, it relies on environmentally friendly and biodegradable vegetable oil as its insulating liquid. This transformer also employs forced air cooling with two stages, with a one-stage power rating of 12.5 MVA and a two-stage rating of 15 MVA.

It features an ingenious sealed tank design, further complemented by an oil preservation system, ensuring heightened performance and longevity.

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Daelim Transformer Solutions

An experienced and efficient communication engineer, purchasing and sales team to connect with customers.

  • Professional communication
  • From transformer design to production, Daelim Transformer's engineers and their partners with customers have repeatedly communicated with each other on the requirements of 230 kV transformer standards, parameters, and accessories to ensure that they meet the requirements of IEEE.
  • Customized design as per special requirements
  • Based on years of experience in the IEEE/ANSI standard overseas market, Daelim Transformer's power transformer engineer team has improved and optimized their existing oil tanks and paint processes to meet the special technical requirements of customers.
  • Business support team assistance
  • Daelim Transformer's business support team has closely collaborated with the customer's logistics team. Daelim Transformer always pays attention to every detail of sea and land transportation and monitors the entire transportation process through the installation of impact recorders. Ultimately, the 230 kV transformer is safely transported to the site.
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Daelim Transformer Solutions

230 kV Transformer Production Process

230 kV Transformer Windings

230 kV Transformer Windings

230 kV Transformer Body

230 kV Transformer Body

230 kV Silicon Steel Sheet

230 kV Silicon Steel Sheet

230 kV Transformer Shipping & Installation

230 kV Transformer Test

230 kV Transformer Test

This transformer has successfully undergone comprehensive testing in accordance with IEEE C57.12.00 and IEEE C57.12.90 standards, with all tests passed at one time.

  • Ratio, Polarity, and Phase Relation Tests: Verified and validated.
  • Winding Resistance Measurement Tests: Conducted and confirmed.
  • Insulation Power Factor: Checked and met the required specifications.
  • Full Wave and Reduced Wave Impulse Test: Completed and found to be within acceptable parameters.
  • Applied and Induced Potential Tests: Successfully performed, meeting stipulated criteria.
  • No-Load Losses at Rated Current: Tested and found to meet standards.
  • Total Losses at Rated Current: Tested and confirmed as per the prescribed guidelines.
  • Percent Impedance at Rated Current: Measured and found to be in compliance with requirements.
  • Dissolved Gas Analysis (DGA) Test: Conducted and results are satisfactory.
  • Leak Test: Performed and validated.
  • Control Cabinet Test: Carried out and met the necessary criteria.

This comprehensive series of tests assures the quality and reliability of the transformer.

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230 kV Transformer Shipping

Daelim Transformer boasts over 20 years of experience in transformer manufacturing and export, making them highly adept in the intricacies of transformer packaging and transportation.

In the case of 230 kV power transformers, with dimensions exceeding three meters in height and a weight surpassing 50 tons, it is common practice to disassemble high-voltage bushings, radiators, fans, and other accessories. Subsequently, the transformer body and these removable components are shipped separately.

Daelim Transformer employs specialized open-top containers to securely house the transformer body, while the detachable accessories are meticulously packed in wooden crates, ensuring their safe transport via a separate container.

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230 kV Transformer Shipping
Installation and Customer Feedback

Installation and Customer Feedback

Displayed below is an image of the transformer installation provided by the customer. Upon receiving the transformer, the customer expressed their utmost satisfaction with various aspects. They noted the overall completeness and aesthetics of the transformer's appearance, indicating their contentment.

Furthermore, the transformer underwent performance testing, aligning fully with IEEE standards or, in some aspects, even surpassing the standard requirements, which pleasantly surprised the customer. They also lauded Daelim Transformer's professional team for their technical expertise, business acumen, effective communication, and exceptional after-sales service. Collaborating with Daelim Transformer proved to be a seamless and swift experience for the customer.

The extensive project experience and professional competence of Daelim Transformer significantly enhanced their competitiveness. The customer has expressed their commitment to maintaining a close and enduring partnership with Daelim Transformer.

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Daelim Transformer

Overseas Project Cases

This 10MVA 230 kV Power transformer is for bitcoin mining in Houston. It was manufactured in our factory in Jiangsu Province and it complies with IEEE standards.

230 kv power transformer

This 20/30MVA 220 kV power transformer was manufactured for a power station in Ecuador.

220kv power transformer

Daelim 220 kV/230 kV transformer, use Japanese Toshiba analysis software and our company's special calculation and validation procedures for the transformer core, winding, implement body, lead, fuel tanks, etc. Parts of the optimal design and carrying on the Omni-directional validation, ensure product performance. Superior process equipment, elaborate material selection, and efficient manufacturing make the transformer have small volume, lightweight, low loss, low partial discharge, low noise characteristics. The product quality is superior, energy conservation and environmental protection, easy installation and maintenance, reliable operation, and effectively reduced product running costs.


Daelim offers transformer solutions such as high efficiency, environmentally friendly, maximum short-circuit strength, overload capability, high-temperature operation, reliable start-up after a power outage, and low maintenance costs solutions, applied in renewable projects, urban substations, utilities, industrial applications, etc.

daelim transformer factory

Daelim Advantages

• Prompt preparation of bids

• Optimized, consistent end-to-end project management

• Noticeably shorter production and delivery times

• Very high delivery reliability

• Fast, standardized documentation

• Just-in-time delivery


220kV/230kV Transformer Details

Core Assembly220kv transformer core assembly

The iron core of the 220kV/230kV power transformer is made of cold rolled, granular-oriented, low-loss, and high magnetic conductive silicon steel sheet, which is of multi-step completely tilted structure to reduce the loss and noise.


Iron core with fixed clamps optimizes the design so as to ensure mechanical strength and reduce leakage losses.

The adoption of PET banding structure ensures the damp force of the core column and lowers the noise.


Coil Winding220kv transformer coil winding


Daelim 220kV and 230kV transformer HV winding adopt entanglement or inner screened continuous type with phase insulation structure to ensure insulating strength.


MV/LV windings adopt high strength or adhibit-transposition conductors and forced cooling to reduce the temperature rise and enhance the capability of short circuit withstand.


Interleaved, shielded disc, helical, disc, or layer construction (depending on voltage and impulse rating)


Active- parts Assembly

Cold pressing ensures the cleanness of the body's active parts and the reliability of leads.


Daelim 220kV and 230kV transformer uses the entire assembly and insulation material to reduce the assembly time and effectively ensure the size and shape of the insulating structure.


HV lead adopts specially molded insulation parts for protection which effectively guarantees its insulating strength and reduces partial discharge.


Vapor phase

vapor phase
Daelim's modern vapor phase system is the quickest and most effective way to dry transformers.


This process ensures the perfect drying of the 220kV transformer, which brings a longer transformer life. Compared with non-steam, the drying of steam will also be reduced by more than 50 %.


Passing this time savings along the production schedule results in quicker delivery.


Oil Tank

The 220 kV 230 kV transformer fuel tank uses the three-dimensional finite element strength analysis and Pro-E mold, which enhances mechanical strength.


Adopting of welding automatic submerged arc-welding and ultrasonic fluorescence leakage test to guarantee leakage-free.

The surface coating is strictly controlled.


Laboratory Test

220 kV 230 kV transformers testing according to ANSI / IEEE C57.12 I IEC 60076 Standards.


Oil Laboratory

The oil in 220KV 230KV Transformer is based on ASTMD-3487 /2002 / IEC 60296 / IEEE C57.106-2002 / IEC 60422 standards for physical and chemical analysis and chromatography.

220kv transformer230kv transformer

220 kV transformer specification

Three-phase three winding non-field excitation changer self-coupling power transformer 
Voltage Combined Step up Combination Step Down Combination
HV(kV) MV(kV) LV(kV) No Load Loss Load Loss No Load Loss Load Loss
31500 kVA




25 117 22 99
40000 kVA 29 144 26 121
50000 kVA 34 170 30 144
63000 kVA 40 201 36 171
90000 kVA 50 276 46 234
120000 kVA 10.5
62 340 56 288
150000 kVA 73 405 66 342
180000 kVA 84 463 76 387
240000 kVA 99 595 89 504


Three-phase duplex winding power transformer on load changer
Voltage Combined No Load Loss Load Loss No Load current Short-circuit impendance
HV(kV) LV(kV)
31500 kVA





38 135 0.7 12-14
40000 kVA 45 157 0.63
50000 kVA 54 189 0.56
63000 kVA 63 220 0.56
90000 kVA 80 288 0.49
120000 kVA 10.5
99 346 0.49
150000 kVA 116 405 0.42
180000 kVA 135 468 0.42
120000 kVA 66
102 355 0.49
150000 kVA 120 415 0.42
180000 kVA 140 475 0.42


Three phase three winding power transformer on load changer
Voltage Combined No Load Loss Load Loss No Load current
HV(kV) MV(kV) LV(kV)
31500 kVA




44 162 0.77
40000 kVA 52 189 0.7
50000 kVA 60 225 0.63
63000 kVA 70 261 0.63
90000 kVA 10.5
92 351 0.56
120000 kVA 115 432 0.56
150000 kVA 135 513 0.49
180000 kVA 156 630 0.49
240000 kVA 193 780 0.45


220 kV Power Transformer Standard Features

Capacity range:Through 60 MVA (ONAN), with high-voltage ratings

through 230 kV (900 kV BIL)

Service Location: Outdoor

Core: Regular grain-oriented; mitered cruciform with step-lap


Coils: Cylindrical construction; all copper windings, custom tempered per design requirements; circular windings with the rectangular or continuously-transposed conductor;

helical low-voltage windings; continuous disc medium-voltage

windings; shielded disc high-voltage windings

Radiators: Detachable panel type with shut-off valves; mild steel

Insulating oil: mineral oil typeⅠ& type Ⅱ

Tank Cover: Welded, Bolted

Manholes: On cover or tank

Tank Base:  Flat bottom or Skid under the base

Tank Material: Mid Steel

Frequency: 60 Hertz

Winding Tem rise: 55℃

HV Taps: DETC, ETC in tank or out

− Above rated volts: 2 x 2-1/2% offload taps of full capacity

Below rated volts: 2 x 2-1/2% offload taps of full capacity

Valve: Drain and Filter Valves, w/Sampler

Lifting, Moving, and Jacking Facilities

Pressure relief valve

Magnetic oil-level indicator

Dial-type oil temperature indicator

Dial-type winding temperature indicator

Dial-type sudden pressure relay

Vacuum pressure gauge

Paint: Exterior polyurethane enamel, ANSI 70 gray color; interior

polyurethane enamel, white color

HV bushing: IEEE segment 1-4, on the top cover or in Air Terminal Chamber.

Porcelain Condenser, Solid Bulk, Solid Dielectric, Quick link

LV bushing: IEEE segment 1-4, Cover mounted or in Air Terminal Chamber Porcelain Condenser, Solid Bulk, Solid Dielectric, Quick link

Diagrammatic nameplate, engraved stainless steel

Transformer lifting lugs

Tank grounding pads


Optional Accessories

Below are optional accessories for Daelim 220kV and 230kV transformers.

230kv transformer optional accessories


Insulating oil: Natural ester( FR3 Enviro Temp, RAPO  etc)                 

 Frequency: 50 Hertz

Average winding rise: 55°C or 55/65°C

Future fan wiring and control

Automatic pressure relief device

Galvanized or stainless-steel radiators


Accessories with additional contacts

Controls Cabinet: NEMA 3R, 4, 4X

Customizable Colors

HV lightning arresters: Distribution Class,

Intermediate Class, Station Class

Harmonic allowances up to k-20

Seismic designs: Zones 1-4

Rapid Rise Relay

Neutral Terminations

Other Moving Facilities (Wheels)                                  

 Nitrogen gas fluid preservation system

Gas Test Valve

Schrader Valve

Junction Box

Fiber-optic temperature measurements

Line Dissolved Gas Monitor

Bushing Mounted Current Transformers

Fire Prevention System (SERGI)

On-line monitoring system

Electrostatic shield

Special/low sound level

Special environment (i.e: classified areas)

Special paint for marine ambient


Quality & Certification System

DAELIM BELEFIC transformer manufacturing processes are standardized under the norm of ISO 9001:2015 quality, allowing us to have greater control over the production

220kv transformer quality certification
We offer a full range of testing compliant with ANSI C57.12 and CSA C88-M90 standards, as well as, specialty testing such as lightning impulse, sound, heat run, partial discharge, and SFRA.

Tests Transformer Class
Class I (≤ 69 kV) Class II (115-765 kV)
Standard Optional Standard Optional
Winding resistance    
Winding insulation resistance    
Core insulation resistance    
Polarity and phase relation    
Insulation power factor    
Control (auxiliary) cooling losses      
Single-phase excitation tests    
Noload losses and excitation current    
Impedance voltage and load losses    
Zero-phase sequence impedance voltage    
Temperature rise    
Low-frequency dielectric tests    
Low-frequency dielectric tests on axiliary devices    
control, and current transformer circuits    
Lightning impulse    
Front of wave impulse    
Swithing impulse    
Partial discharge    
Audible sound level    
Operational tests (all devices)    
Dissolved gases in oil    
Leak test        


Service & Support

DAELIM BELEFIC will work with you to identify your transformer needs and customize the solution. Once we know your exact requirements, our engineers will quickly recommend the right solution based on your specific needs.
Expertise&consulting&: To meet performance requirements we are able to incorporate short circuit strength improvements, kVA upgrades, voltage changes, reduced losses, LTC modernization, sound level reduction, and tank modification. Our engineering team responds fast to answer technical questions from our customers.

  1. Factory-to-Jobsite logistics support Delivery by ship and truck, the impact recorders measure and store three-axis impact data, identifying any abnormally severe impacts that might have caused damage to the transformer during transportation.
  2. On-Site Technical Assistance: In Assembly, Oil Treatment, Testing, and Commissioning (Energization) by an Engineer 
  3. Training:by a Factory Specialist, about the operation and maintenance
  4. Repair: Our technicians replace gaskets, broken bushings, and accessories, purify or replace the oil, sand, prime, and repaint the unit. When complete, the unit is fully tested.

110kv transformer115kv transformer