Transformers
66kV 69kV Power Transformer
Ensure robust and ultra-efficient power transformation at high voltage levels with our 66kV and 69kV Power Transformers. These vital components are indispensable for main transmission substations, large industrial power grids, and significant renewable energy plants. Our 66kV and 69kV Power Transformers are precision-engineered with advanced oil-immersed designs and sophisticated cooling systems (ONAN, ONAF, OFAF), guaranteeing exceptional efficiency, ultra-low losses, superior dielectric strength, and high short-circuit withstand capability. Built for continuous, heavy-duty operation in the most demanding environments, they ensure stable and uninterrupted power flow. Trust our compliant and custom-tailored solutions for your critical high-voltage power transformation needs.
66kV 69kV Power Transformer
66 69kV power transformer uses high-performance silicon steel sheets and a fully sealed structure design, with excellent insulation performance and thermal stability. The product complies with international and national standards, such as 1 . IEC 60076 Power Transformers; 2. AS NZS 60076 Power Transformers CSAC88-16 Power Transformers 3.ANSI/IEEE C57.12.00 IEEE Standard for General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers; 4. GOST R 52719 Power Transformers - General Specifications; 5. EN60076 Poer Transformer;8. Local After-Sales Services In North America South
50kV 1000kVA Outdoor Three-Phase Oil-Immersed Power Transformer for Distribution
The 50kV 1000kVA Outdoor Three-Phase Oil-Immersed Power Transformer for Distribution is engineered to deliver high efficiency, stable voltage regulation, and long-term service reliability in medium-voltage distribution networks. Designed for outdoor installation, the transformer features a robust oil-immersed cooling system, high-grade silicon steel core, and pure copper windings to ensure excellent thermal performance and low-loss characteristics. Its rugged, weatherproof construction withstands harsh climates, ensuring continuous operation in industrial plants, utility grids, mining sites, and renewable energy distribution stations. With optimized insulation, superior dielectric strength, and advanced protection configurations, the transformer offers enhanced safety and reduced maintenance. This unit is ideal for step-down power distribution scenarios requiring consistent performance and dependable energy delivery.
55kV 1600kVA Three Phase Oil Immersed Power Transformer Copper
The 55kV 1600kVA Three Phase Oil Immersed Power Transformer Copper is designed for reliable medium/high-voltage distribution networks. It adopts 99.95 % electrolytic copper windings, Class A insulation, a corrugated-fin tank, and ONAN cooling for excellent heat dissipation. Available in energy-saving S11/S13 series with no-load loss reduced by up to 35 %. Fully sealed or conservator type prevents oil aging. Equipped with ±5 % or ±2×2.5 % off-circuit tap changer (on-load optional). Meets IEC 60076, GB/T 1094 standards, lightning impulse withstand 250 kV peak, PD <10 pC. Low noise (<58 dB), strong short-circuit strength, suitable for harsh environments. Vacuum oil filling + nitrogen sealing ensures a 30+ year lifespan. Widely trusted in mining, petrochemical, renewable energy, and urban 55 kV substations.
60kV Dyn11/Yyn0 Pure Copper Oil-Immersed Power Transformer
The 60kV Dyn11/Yyn0 Pure Copper Oil-Immersed Power Transformer is designed for regional 35–50 kV distribution networks and industrial substations. It adopts 99.99 % electrolytic pure copper windings, Class A insulation, corrugated tank + ONAN natural cooling, and energy-saving S11/S13 core with up to 40 % lower no-load loss. Standard vector groups Dyn11 or Yyn0, off-circuit tap changer ±5 % or ±2×2.5 % (on-load optional). Fully compliant with IEC 60076, lightning impulse 250 kV peak, PD <10 pC. Fully sealed or conservator design prevents oil aging and moisture ingress. Low noise ≤58 dB, strong short-circuit withstand, suitable for high-altitude and harsh environments. Vacuum oil filling + nitrogen sealing ensures>30-year lifespan. Widely used in mining, petrochemical, renewable energy, and urban 50 kV networks.
65kV Three-Phase Oil-Immersed Power Transformer with No-Load Voltage Regulation
The 65kV Three-Phase Oil-Immersed Power Transformer with No-Load Voltage Regulation is engineered for medium-to-high voltage distribution systems requiring stable performance and precise voltage control. Equipped with a no-load tap changer, the transformer allows flexible adjustment of voltage ratios to meet varying grid demands. Its high-grade silicon steel core and oxygen-free copper windings ensure low losses, superior thermal efficiency, and long operational life. The oil-immersed cooling system provides enhanced heat dissipation, while the durable outdoor-rated tank structure enables reliable operation in harsh climatic environments. Designed in compliance with IEC, IEEE, and GB standards, this transformer is widely used in utility substations, industrial power networks, renewable energy stations, and large commercial distribution systems. It delivers consistent voltage regulation, strong overload capability, and dependable long-term grid support.
70kV 8000kVA Copper-Wound Oil-Immersed Power Transformer for High-Voltage Distribution
The 70kV 8000kVA Copper-Wound Oil-Immersed Power Transformer for High-Voltage Distribution is designed to deliver robust performance in demanding grid environments. Featuring 100% oxygen-free copper windings, the transformer ensures superior electrical conductivity, reduced losses, and enhanced overload capability. Its oil-immersed cooling system provides excellent heat dissipation, maintaining long-term stability under high-load and continuous operation conditions. The high-grade silicon steel core minimizes noise and magnetic losses, improving overall efficiency. The transformer’s reinforced tank, durable insulation system, and outdoor-ready structure enable reliable operation in harsh climates, industrial zones, and high-temperature regions. Compliant with IEC, IEEE, and GB standards, this transformer supports utility substations, industrial power networks, renewable energy integration, and high-voltage distribution systems, ensuring safe, efficient, and uninterrupted power delivery.
75kV 1250kVA Three Phase Oil Immersed Power Transformer Copper
The 75kV 1250kVA Three Phase Oil Immersed Power Transformer Copper is engineered for regional 66–75 kV transmission and industrial step-down applications. It adopts 99.99 % electrolytic copper windings, high-grade grain-oriented silicon steel S13 core, corrugated tank + ONAN cooling, and ±5 % off-circuit tap changer (on-load optional). Fully compliant with IEC 60076, lightning impulse withstand 350 kV peak, PD <10 pC, noise ≤58 dB. Fully sealed or conservator design with vacuum oil filling and nitrogen sealing ensures >30-year maintenance-free operation even in high-altitude or polluted areas. Ideal for mining, metallurgy, wind farms, and urban 75 kV substations requiring high reliability and low loss.
85kV 1850kVA Outdoor Oil Immersed Distribution Transformer Copper
The 85kV 1850kVA Outdoor Oil Immersed Distribution Transformer Copper is specially developed for 66–110 kV regional distribution networks and industrial users. It adopts 99.99 % electrolytic copper windings, high-permeability S13 grain-oriented silicon steel core, corrugated-fin tank + ONAN natural cooling, and ±5 % off-circuit tap changer (on-load optional). Fully compliant with IEC 60076, lightning impulse withstand 395 kV peak, PD <10 pC, noise ≤60 dB. Fully sealed conservator or sealed-type design with vacuum oil filling + nitrogen sealing guarantees >30-year maintenance-free operation even in high-altitude, high-pollution, or coastal areas. Ideal for mining, metallurgy, wind/solar grid connection, petrochemical plants, and urban 85 kV substations requiring maximum reliability and minimum losses.
90kV Three-Phase Oil-Immersed Power Transformer
The 90kV Three-Phase Oil-Immersed Power Transformer for High-Voltage Distribution is engineered to deliver reliable and efficient performance across utility grids, industrial substations, and high-voltage transmission systems. Designed with high-grade silicon steel cores and 100% copper windings, the transformer ensures low losses, strong short-circuit resistance, and stable thermal performance. Its oil-immersed cooling structure provides superior heat dissipation, supporting continuous and heavy-duty operation. The robust tank, high-performance insulation system, and outdoor-ready protection structure enable safe operation in harsh climate conditions. Compliant with IEC, IEEE, and GB standards, the transformer offers excellent voltage stability, long service life, and high operational reliability. It is widely used in power utilities, infrastructure projects, renewable energy integration, and industrial distribution networks requiring dependable high-voltage transformation.In-Depth Analysis
Power transformers are built to deliver high efficiency, reliable performance, and advanced safety, helping businesses reduce energy costs while ensuring stable power supply. With future-ready adaptability for renewable energy and smart grid applications.
Comparative Analysis of Efficiency and Loss
Compared to the industry average, transformers exhibit lower losses and higher efficiency across the entire load range.
Load Efficiency Comparison(%)
No-load Loss Comparison(W)
High-efficiency Core Design
High magnetic permeability and low loss silicon steel sheets are used and processed by special process to reduce hysteresis loss and eddy current loss and improve conversion efficiency.
Improved Magnetic Permeability
+30%
Reduced Iron Loss
-35%
Multiple Protection Systems
IP65 protection grade design combines multiple protection measures such as anti-corrosion, anti-UV, anti-condensation and anti-small animal intrusion.
Waterproof Performance
IP65
Anti-Corrosion Ability
15 years+
Ultra-low Noise Technology
A special shock-absorbing structure, low-noise fans, and optimized heat dissipation design ensure operating noise is far below industry standards.
Noise Reduction
-15dB
Suitability for Residential Areas
Excellent
Intelligent Cooling System
The heat dissipation system with adaptive temperature control automatically adjusts the heat dissipation efficiency according to the load and ambient temperature to reduce energy consumption.
Heat Dissipation Efficiency
+40%
Temperature Stability
±2℃
Safety Wiring System
Insulated protective cover and anti-misoperation design ensure personnel safety during installation and maintenance and reduce accident risks
Insulation Grade
Class H
Safety Protection
IP2X
Intelligent Monitoring
An optional remote monitoring system is available to monitor operating status, temperature, load and other parameters in real time, and supports fault warning and remote diagnosis.
Data Collection Frequency
one times a minute
Fault Warning Accuracy
96%
Environmental Adaptability Analysis
Power transformers have been rigorously tested and can operate stably under various harsh environmental conditions.
Temperature Range
-40℃ ~ +55℃
Can work normally in extreme high and low temperature environments
Humidity Adaptation
0 ~ 100% RH
Including condensation environment, no frost requirement
Seismic Resistance Level
IEC 60068-2-57
Suitable for earthquake-prone areas
Altitude
≤3000m
More than special design
Why Choose Us
Discover why our power transformers are trusted worldwide for efficiency, safety, and reliability.
Engineered for High Voltage Transmission
NPC Electric 66kV and 69kV Power Transformers are precisely engineered for high voltage transmission, making them indispensable for main substations and large-scale power distribution. Designed to handle the unique demands of these elevated voltage levels, they ensure secure and efficient power flow across vast distances and between different sections of the grid. This specialization guarantees optimal performance and stability in critical high-voltage networks. By choosing our high voltage transformers, you equip your power infrastructure with robust and reliable assets, fundamental for maintaining the integrity and capacity of your transmission grid.
Ultra-High Efficiency & Minimal Losses
We design our 66kV and 69kV Power Transformers for ultra-high efficiency and minimal losses, significantly contributing to grid sustainability and operational savings. Utilizing advanced magnetic core materials, optimized winding configurations, and sophisticated cooling systems (like ONAF/OFAF), these transformers achieve industry-leading low no-load and load losses during voltage conversion. This ensures maximum power delivery to consumers and minimal energy waste. By deploying our ultra-efficient power transformers, you not only enhance the overall performance of your high-voltage transmission network but also achieve substantial long-term cost reductions, maximizing your investment in power transformation.
Unmatched Reliability & Robust Construction
NPC Electric 66kV and 69kV Power Transformers boast unmatched reliability and robust construction, built for continuous, heavy-duty operation in the most challenging environments. These oil-immersed units feature high-grade insulation, durable enclosures, and advanced protection systems, ensuring superior dielectric strength and exceptional short-circuit withstand capability. Each transformer undergoes rigorous testing to guarantee long-term operational stability and resilience against electrical stresses and external factors. By selecting our reliable high-voltage transformers, you invest in critical equipment that provides unwavering power flow, safeguarding your transmission substations and large industrial loads against disruptions.
Customized Solutions for Complex Grid Needs
NPC Electric provide customized solutions for our 66kV and 69kV Power Transformers, precisely meeting the complex demands of modern high-voltage grids and large-scale projects. Our expert engineering team collaborates closely to design units with specific MVA ratings, impedance values, advanced tap changer options (OLTC), and specialized cooling configurations. Whether for new transmission lines, large industrial complexes, or renewable energy integration, we deliver tailored designs that optimize performance, space, and cost-efficiency. By choosing our custom high-voltage transformers, you acquire a perfectly engineered solution that integrates seamlessly into your electrical infrastructure, ensuring peak performance and adaptability for future grid requirements.
Product Show
Explore the detailed design and practical application scenarios of power transformers
220kV Electrical Transformer
220kV transformer product show
350kV Power Transformer
350kV transformer product completed
Step Up Power Transformer
step up transformer is a power transformer
Step Up Transformer Font
step up transformer font view
Power Transformer Oil Temperature
transformer oil temperature design
750kV Power Transformer
750kV transformer design struture
Power Transfomer Oil Conservator
transfomer oil conservator design
Power Transformer Produce Line
worker produce power transformer
Testing and Certification
Tested with precision and certified to meet international standards as
well as strict industry requirements.
Bare Cable Test Report
SGS Inspection Report
Certificate of Acceptance
ISO Quality Certificate
ISO Environmental Certificate
ISO Occupational Certificate
UL Laboratory Certificate
UL Product Certificate
Project Cases
Power transformers have been successfully applied in many projects and have been highly praised by customers.
Venezuela Residential Area
CompletedProvide stable and reliable power conversion solutions for the residential area to meet diverse production needs.
Country：Venezuela
Model：220kV Power Transformer x 5
Uruguay Data Center
CompletedEnsure the power safety of surrounding residents and meet daily work needs
Country：Uruguay
Model：350kV Power Transformer x 10
Dominican Factory
CompletedNPC transformers provide safe, efficient, and reliable power distribution in the Dominican.
Country：Dominican
Model：450kVA Power Transformer x 4
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
FAQ From Customers
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What are 66kV and 69kV Power Transformers primarily used for?
66kV and 69kV Power Transformers are vital for high-voltage power transmission and distribution. They are primarily used in main substations, large industrial facilities, and major renewable energy plants to efficiently step up or step down voltage, ensuring stable power flow across the grid. -
What makes your 66kV/69kV Power Transformers ultra-efficient?
Our 66kV/69kV Power Transformers achieve ultra-high efficiency through optimized core designs, premium magnetic materials, and advanced winding configurations. This minimizes no-load and load losses, leading to significant energy savings and reduced operational costs for high-voltage networks. -
Can these high-voltage transformers be customized for specific project requirements?
Absolutely. We offer customized solutions for our 66kV and 69kV Power Transformers. Our engineering team can tailor specifications such as MVA ratings, impedance, tap changer types (OLTC/OCTC), and cooling systems (ONAF, OFAF) to perfectly integrate with your unique high-voltage grid infrastructure. -
What cooling systems are typically integrated into your 66kV/69kV Power Transformers?
NPC Electric 66kV/69kV Power Transformers predominantly use oil-immersed designs with advanced cooling systems to manage heat effectively. Common methods include ONAN (Oil Natural Air Natural), ONAF (Oil Natural Air Forced), and OFAF (Oil Forced Air Forced), selected based on the transformer's capacity and application demands. -
How do your 66kV and 69kV Power Transformers ensure grid reliability?
Our 66kV and 69kV Power Transformers ensure grid reliability through robust construction, superior dielectric strength, and high short-circuit withstand capability. These features, combined with precise voltage regulation, prevent failures, minimize downtime, and guarantee consistent power quality in critical high-voltage transmission networks.
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