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Discover why oil immersed transformers remain the backbone of global power distribution. Learn about their advantages, key applications in utility grids, renewable energy, and industrial plants, and how TSTY Electric delivers high-quality IEC/CQC/CE certified transformers worldwide.

Introduction: The Indispensable Role of Oil Immersed Transformers

The global transformer market is experiencing unprecedented growth, driven by rising electricity demand, grid modernization, and renewable energy integration. According to Persistence Market Research, the global transformer market is projected to grow from 65.7billionin2026to65.7billionin2026to96.8 billion by 2033 at a CAGR of 5.7%. At the heart of this market expansion lies the oil immersed power transformer—a proven, durable technology that has powered the world for over a century.

Oil immersed transformers remain the preferred choice for demanding applications such as utility substations, industrial manufacturing plants, renewable energy farms, and mining operations. Their ability to handle high voltage and heavy loads while delivering decades of reliable service makes them indispensable to modern power infrastructure. In this article, we will explore the technical advantages, diverse applications, and emerging market trends of oil immersed transformers—and why TSTY Electric is your trusted partner for high-quality transformer solutions.

What Makes Oil Immersed Transformers Superior?

The core design of an oil immersed transformer involves submerging the core and windings in insulating mineral oil or environmentally friendly ester oil. This oil serves two critical functions: electrical insulation and heat dissipation. The insulating oil efficiently transfers heat generated by the windings and core to the transformer tank and external cooling surfaces, allowing oil immersed transformers to handle significantly higher power ratings and overload conditions compared to dry-type alternatives.

One of the most significant advantages of oil immersed transformers is their superior heat dissipation performance. Mineral oil provides 8-to-12 times better heat dissipation than air-cooled dry-type units, enabling more compact designs at high power ratings. The oil also acts as a thermal buffer during temporary spikes, ensuring continuous operation even under demanding load conditions.

In addition to cooling, transformer oil offers excellent dielectric properties, enhancing insulation reliability and reducing the risk of partial discharge and insulation aging. With proper maintenance, oil immersed transformers can operate reliably for 30 to 40 years, delivering a lower total cost of ownership compared to other transformer types.

Critical Applications Across Industries

Oil immersed transformers are deployed across a wide spectrum of applications where reliability and high capacity are essential.

In power transmission and distribution, these transformers serve as backbones of high-voltage substations, stepping down transmission voltages to levels suitable for distribution networks while maintaining consistent voltage levels and minimizing energy losses. Utility grids worldwide rely on oil immersed units for reliable voltage regulation.

In industrial manufacturing, they provide reliable power for heavy machinery, motors, and variable production loads in steel plants, cement factories, chemical facilities, and mining operations—ensuring stable power under extreme thermal and mechanical stress.

Renewable energy integration represents a rapidly growing application. Wind and solar farms require heavy-duty transformers to convert intermittent generation into grid-ready power, and mounting global renewable capacity is creating new transmission needs that drive this demand.

Urban infrastructure—including metropolitan rail systems, airports, hospitals, and data centers—also relies on oil immersed transformers installed in traction substations to provide stable voltage for critical systems. Data center expansion itself drives transformer demand, with an estimated 74 GW of new electricity demand expected from U.S. data centers by 2028.

Technological Advancements and Energy Efficiency

Modern oil immersed transformers incorporate advanced technologies to improve efficiency, environmental sustainability, and intelligence. The mandatory GB 20052-2024 energy efficiency standard, effective February 2025, has raised the bar for transformer performance, requiring Tier 1 units to achieve 30-to-50 percent lower losses compared to Tier 3 models.

Innovations include amorphous alloy cores that reduce no-load losses by up to 70 percent compared to traditional S13 models, biodegradable ester oils that improve safety and reduce environmental impact, and smart monitoring systems that enable predictive maintenance and remote control.

TSTY Electric: Your Trusted Transformer Partner

TSTY Electric Co., Ltd., with over 30 years of power equipment manufacturing expertise and a National High-Tech Enterprise certification, offers a comprehensive range of oil immersed transformers designed to meet international standards. Our product line includes S9, S11, S13, S20, and S22 series, covering voltage ratings from 6.6 kV up to 220 kV and capacities from 15 kVA to 31,500 kVA.

Key technical characteristics of TSTY oil immersed transformers include fully sealed construction for maintenance-free operation, low loss and low noise design, high short-circuit resistance with no leakage, on-load tap changers for voltage regulation under load, and optional remote control capabilities for unmanned substation operation.

All TSTY products are backed by ISO 9001 factory certification and meet IEC, CQC, SGS, CE, and GOST standards, ensuring global competitiveness and reliability.

Conclusion: Power Your Future with TSTY

As the global transformer market continues its strong growth trajectory—driven by grid modernization, renewable energy integration, and industrial expansion—choosing the right transformer partner is more important than ever. TSTY Electric delivers high-quality oil immersed transformers engineered for demanding environments, with a full lifecycle service system and a proven track record in over 80 countries.

For custom solutions, technical specifications, or a competitive quote for your upcoming power infrastructure project, contact the TSTY Electric team today.

Contact TSTY Electric 🌐 Website: www.tstynice.com 📞 Telephone: +86-18135684124 ✉️ E-mail: [email protected]

As the world accelerates toward a low-carbon future, energy storage has become the backbone of modern power systems. The global energy storage market is projected to maintain over 20% annual growth through 2030, driven by rising renewable penetration and the urgent need for grid flexibility. Among the most critical technologies enabling this transition is the Energy Storage Converter and Step-Up Integrated Unit—a compact, intelligent system that bridges renewable generation, battery storage, and the utility grid.

TSTY Electric Co., Ltd., with over 30 years of power equipment expertise and a national “Specialized and Innovative Little Giant” recognition, offers a complete line of integrated PCS and step-up solutions. These units are available in European, American, and Chinese standard configurations, ensuring compatibility with diverse global markets.

What Is an Energy Storage Converter and Step-Up Integrated Unit?

This all-in-one system integrates a power conversion system (PCS), a step-up transformer (either dry-type or oil immersed), high-voltage and low-voltage switchgear, and intelligent monitoring into a single enclosure. Its core function is to store electricity from solar, wind, or grid during off-peak hours, then convert and boost the voltage for stable grid feeding or local use when demand rises. By smoothing renewable intermittency and enabling peak shaving, it significantly improves grid stability and energy efficiency.

Key Features and Benefits

Highly Integrated and Space-Saving: Factory prefabricated and pre-commissioned, the unit reduces on-site installation time by about 50%, accelerates project commissioning, and lowers civil works costs.

Smart and Remote Ready: Real-time monitoring of voltage, current, temperature, and battery status. Supports SCADA and cloud-based control for unmanned operation and predictive maintenance.

Robust Environmental Adaptability: IP54 protection for compartments and IP68 for oil-immersed transformer tanks. Operates reliably from -40°C to +50°C, with anti-corrosion, anti-sand, and anti-UV designs for deserts, coastal areas, and high-altitude regions.

Safety and Efficiency: Uses flame-retardant oil-immersed or dry-type transformers, optional automatic fire suppression, and low-loss amorphous alloy cores. Harmonic mitigation (THD < 3%) ensures power quality.

Applications Across Sectors

Renewable Power Plants: Smooths output from solar farms and wind power stations, ensuring grid compliance.

Commercial & Industrial Facilities: Peak-valley arbitrage, demand management, and emergency backup for factories, data centers, shopping malls, and hospitals.

Microgrids & Off-Grid Areas: Independent power supply for islands, mining sites, and rural communities, often combined with diesel or solar.

Grid Ancillary Services: Frequency regulation, spinning reserve, and load following.

Why TSTY Electric?

TSTY’s energy storage step-up units are backed by a CNAS-accredited lab, 158 core patents, and international certifications including IEC, UL, CE, and GOST. With products exported to over 80 countries and a 24/7 global service network, TSTY delivers reliability and performance. Whether you need a compact 100kW system for a commercial building or a large containerized solution for a utility-scale project, TSTY provides end-to-end engineering, fast delivery, and lifelong after-sales support.

 TSTY ELECTRIC – Dedicated Compact Substation for Renewable Energy Generation

TSTY ELECTRIC proudly presents its Dedicated Compact Substation for Renewable Energy Generation – a high‑performance, prefabricated high‑voltage/low‑voltage substation that integrates high‑voltage switchgear, transformer core, protective fuses (all inside the oil tank), low‑voltage switchgear, and complete auxiliary equipment into one compact unit.

Designed as a dedicated step‑up solution, it raises the voltage from renewable energy grid‑tied inverters (or AC generators) to 10 kV or 35 kV, then efficiently delivers power to the grid via a 10 kV or 35 kV line. It is the ideal companion for solar, wind, and other renewable energy systems.

Why Choose TSTY ELECTRIC’s Substation?

Compact structure, small footprint; external radiator for superior heat dissipation : TSTY maximises space efficiency – perfect for distributed renewable projects.

Incorporates our latest transformer series technology – rational structure, safe and reliable : Engineered by TSTY with decades of electrical expertise.

Transformer oil serves as insulating medium for 10 kV or 35 kV side, greatly reducing safety clearances : Safer & more compact – a result of TSTY’s innovative oil‑immersed design.

Fully enclosed enclosure isolates oil from atmosphere, reducing oxidation and moisture ingress; fin‑type radiators for easy disassembly and simple maintenance : TSTY’s sealed architecture ensures long‑term system stability and low maintenance.

Special shot‑blasting surface treatment – excellent anti‑corrosion, anti‑solar radiation, and sand‑erosion resistance : Ruggedised for harsh environments – a hallmark of TSTY quality.

Low‑voltage side uses latest intelligent circuit breakers and moulded case air circuit breakers – high breaking capacity, excellent protection : TSTY integrates advanced LV protection for maximum operational safety.

Transformer tank can be equipped with pressure gauges / thermometers with communication interfaces; load switch can be fitted with limit switch – enabling remote monitoring, operation and maintenance : Smart ready – TSTY supports remote SCADA and IoT integration.

Fully sealed enclosure – IP54 for HV/LV compartments, IP68 for the transformer itself : Highest protection class – TSTY guarantees reliability even in extreme conditions.

TSTY ELECTRIC – Your Trusted Partner in Renewable Energy

As the global energy transition accelerates and energy efficiency standards for power equipment continue to rise, dry-type transformers are rapidly becoming the core choice for power distribution systems. Whether in high-rise buildings, data centers, rail transit systems, or renewable energy plants, dry-type transformers – with their outstanding safety, environmental friendliness, and maintenance‑free operation – are replacing traditional oil‑immersed transformers as the “new standard” in many fields.

This article provides a comprehensive overview of dry-type transformer technology, market trends, regulations, and application scenarios, offering professional guidance for your equipment selection and procurement.

1. What Is a Dry-Type Transformer?

A dry-type transformer is a transformer whose core and windings are not immersed in insulating oil. Its key technical feature is the use of air or solid insulating materials (such as epoxy resin or Nomex paper) instead of conventional transformer oil. Cooling is achieved by natural air circulation (AN) or forced air cooling (AF). Under AN conditions, the transformer can operate continuously at rated capacity; with AF, the output capacity can be increased by about 50%.

The operating principle is based on Faraday’s law of electromagnetic induction: the magnetic core transfers magnetic energy, and the difference in turns between the high‑voltage and low‑voltage windings changes the voltage level. The process involves no moving parts, and energy conversion efficiency typically exceeds 95%.

2. Key Advantages of Dry-Type Transformers

Compared to traditional oil‑immersed transformers, dry‑type transformers offer the following core benefits:

2.1 Safe, Fire‑Resistant & Pollution‑Free

Because they contain no oil, dry‑type transformers eliminate the risk of fire or explosion caused by oil leakage. Windings are encapsulated with epoxy resin or Nomex insulation, achieving a UL94 V‑0 fire rating – ideal for confined spaces such as subways and hospitals. Moreover, they can be installed close to the load center without requiring a separate transformer room, saving valuable building space.

2.2 Low Maintenance & Lower Total Cost of Ownership

There is no need for regular oil level checks, oil quality tests, or oil replacement. Routine maintenance is limited to periodic cleaning and inspection of fasteners. Maintenance intervals can be extended by more than 30%, significantly reducing long‑term operating costs.

2.3 Low Losses, Low Noise, High Efficiency

Dry‑type transformers have 10‑20% lower no‑load losses and 5‑10% lower load losses than conventional oil‑immersed units, meeting the latest national energy‑efficiency standards. For the same core material, Tier 1 (highest efficiency) dry‑type transformers offer the greatest energy savings. Operating noise is typically below 55 dB thanks to optimized design, making them suitable for indoor installation.

2.4 High Adaptability & Wide Application Range

Dry‑type transformers can operate normally at altitudes up to 3000 m and withstand temperatures from -30 °C to +50 °C. Anti‑humidity and anti‑salt‑spray designs make them suitable for coastal or damp environments. By 2025, mainstream products have achieved IP67 ingress protection and can operate reliably from -40 °C to 150 °C.

2.5 Environmentally Friendly – Supporting the “Dual Carbon” Goals

Dry‑type transformers emit no harmful substances during operation and do not require SF₆ (a greenhouse gas) as an insulating medium. More than 95% of their materials can be separated and recycled. Under China’s “Dual Carbon” strategy, dry‑type transformers have become the preferred choice for green power infrastructure.

3. Industry Standards & Energy Efficiency Policies

3.1 Key National Standards

GB/T 10228-2023 Technical parameters and requirements for dry‑type power transformers – Effective since December 1, 2023, for indoor three‑phase dry‑type transformers with rated capacity ≥30 kVA and voltage classes 6/10/20/35 kV.

GB 20052-2024 Minimum allowable values of energy efficiency and energy efficiency grades for power transformers – A mandatory national standard effective from February 1, 2025, adding energy efficiency requirements for transformers used in renewable energy generation.

GB/T 1094.11-2022 Power transformers – Part 11: Dry‑type transformers – The Chinese adoption of the corresponding IEC standard.

3.2 Energy Efficiency Upgrade Policy

Since 2025, China’s National Development and Reform Commission (NDRC) and other authorities have continued to promote transformer energy efficiency improvements. Grid companies have phased out all S7 transformers and distribution transformers that have been in operation for more than 25 years and do not meet the minimum energy access level. The share of energy‑efficient transformers (those meeting Tier 2 or above) in operation has increased by more than 10 percentage points compared to 2021.

Notably, GB 20052-2024 requires that Tier‑1 dry‑type transformers have no‑load losses at least 30% lower than the Tier‑3 access threshold. Choosing high‑efficiency dry‑type transformers is therefore not only an environmental responsibility but also an effective way to reduce costs and increase profitability.

4. Global Market Trends & Outlook

According to leading market research firms, the global dry‑type transformer market is growing strongly:

2025 global market value: ~US$6.83 billion

Forecast 2026–2034: from ~US$7.18 billion (2026) to ~US$12.15 billion (2034) at a CAGR of 6.80%.

Asia‑Pacific leads the global market, holding 36.02% of the share in 2025, driven by rising power infrastructure investment and rapid urbanisation.

The U.S. dry‑type transformer market is expected to reach US$2.64 billion by 2032, supported by renewable energy grid integration and grid modernisation.

In China, driven by the 15th Five‑Year Energy Plan, the domestic dry‑type transformer market is forecast to reach 28.6 billion RMB in 2026, with energy saving, intelligence, and scenario‑specific customisation as the main development directions.

Emerging Application: Data Centres

The market for dry‑type transformers used in data centres is booming. In 2025, global revenue from data‑centre dry‑type transformers was approximately RMB 7.89 billion, and by 2032 it is expected to approach RMB 19.21 billion, with a CAGR of 13.6% – far above the industry average. The rapid construction of AI computing centres and edge data centres is becoming one of the strongest growth engines for the dry‑type transformer market.

5. Typical Applications of Dry‑Type Transformers

Thanks to their unique technical advantages, dry‑type transformers are widely used in many critical fields:

5.1 Commercial Buildings & High‑Rise Towers

Dry‑type transformers can be installed inside electrical rooms on intermediate floors, eliminating the need for a dedicated transformer substation – a perfect fit for super high‑rise buildings. For example, the Ping An Finance Centre in Shenzhen uses dry‑type transformers with a three‑dimensional heat dissipation structure, increasing power density by 30% and reducing footprint by 25%.

5.2 Data Centres & Cloud Infrastructure

Dry‑type transformers are the preferred medium‑to‑low voltage conversion device for data centres, especially in high‑density or confined spaces. Their excellent overload capability, minimal environmental impact, and quieter operation make them widely used in hyperscale and edge data centres. The newer, ultra‑efficient SCB18 dry‑type transformers are becoming the go‑to choice for data centres pursuing extreme energy savings.

5.3 Rail Transit & Airports

The fire‑resistant and low‑noise characteristics of dry‑type transformers make them ideal for subways, high‑speed railway stations, and airports. On Guangzhou Metro Line 18, compact dry‑type traction transformers reduced weight by 40%, perfectly meeting tunnel clearance constraints.

5.4 Renewable Energy Power Plants

Offshore wind farms and photovoltaic (PV) stations require transformers with high weather resistance and corrosion resistance. The anti‑salt‑spray dry‑type transformers used at the Yangjiang offshore wind farm in Guangdong have a maintenance‑free period extended to 10 years.

5.5 Industrial Plants & Chemical Parks

In semiconductor fabs and chemical plants – where electromagnetic interference (EMI) sensitivity or explosion‑proof requirements are high – dry‑type transformers also excel. TSMC’s Nanjing fab selected low‑noise dry‑type transformers with EMI intensity controlled below 1 V/m, ensuring the accuracy of lithography equipment.

6. How to Choose the Right Dry‑Type Transformer

When planning a project, consider the following factors:

6.1 Energy Efficiency Class

Give priority to Tier 1 or Tier 2 products. For example, the SCB18 series currently offers the highest energy efficiency among dry‑type transformers in China, with no‑load losses approximately 10‑15% lower than the SCB14 series and load losses 5‑8% lower.

6.2 Rated Capacity & Voltage Class

Select capacity based on the load profile, leaving a 10‑20% margin. For impact loads (e.g., motor starting), consider the starting current (typically 5‑7 times the rated current) and choose a model with fast dynamic response.

6.3 Environmental Adaptability

High temperature → Prefer Class H or Class C insulation.

High humidity → Choose anti‑condensation design.

Coastal or chemical plants → Opt for anti‑salt‑spray and anti‑corrosion types.

6.4 Smart Features

Modern dry‑type transformers can integrate fibre‑optic temperature sensing, IoT terminals, and RS485/Modbus communication interfaces, allowing seamless connection to building automation systems or energy management platforms for remote monitoring and fault alerts.

6.5 Manufacturer Qualifications

Select a manufacturer with national fixed‑point production qualifications, ISO quality system certification, and international approvals (UL, CE, etc.) to ensure product quality and after‑sales support.

7. Conclusion – Meet TSTY ELECTRIC at the 139th Canton Fair

Dry‑type transformers are core components of modern power systems and are facing unprecedented opportunities. Whether you are planning a commercial complex, a data centre, a renewable energy project, or upgrading the distribution system for a factory or industrial park, choosing a reliable and efficient dry‑type transformer is a critical step toward project success.

TSTY ELECTRIC has many years of experience in the electrical equipment manufacturing industry, focusing on the R&D and production of high‑quality dry‑type transformers. Our products are exported to many countries and regions around the world. We cordially invite you to visit us at the 139th Canton Fair for face‑to‑face discussions!ItemDetailsEvent139th Canton Fair (China Import and Export Fair)DateApril 15–19, 2026VenueCanton Fair Complex, Guangzhou, ChinaBooth No.16.3C03

We look forward to meeting you in Guangzhou to discuss power system optimisation and a greener future together!

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Where Oil Immersed Transformers Shine – Real-World Applications

Oil immersed transformers are the workhorses of global power infrastructure. Thanks to their robust design, high overload capacity, and excellent heat dissipation, they perform reliably in some of the harshest environments on earth.

1. Solar & Wind Farms Renewable energy projects often sit in remote areas – deserts, coastlines, or highlands. TSTY’s oil immersed transformers handle temperature swings from -40°C to +70°C, with corrosion-resistant coatings for offshore wind and coastal solar farms.

2. Industrial Power Distribution Mines, oil & gas facilities, and manufacturing plants demand continuous operation. Our transformers provide stable voltage regulation and withstand frequent load changes, keeping production lines running.

3. Grid & Substation Backbone From 11kV distribution networks to 220kV transmission lines, oil immersed transformers step voltage up or down efficiently. They are the core of compact substations and prefabricated substations for urban and rural grids.

4. Emergency & Mobile Substations When a transformer fails, every hour counts. Our units are available for quick replacement, with options for mobile substation rentals to restore power rapidly.

Why TSTY? With 30 years of experience, IEC/CE/SGS certifications, and 80+ countries served, TSTY delivers oil immersed transformers that are built to last – and backed by global support.

 Why Global Power Projects Trust TSTY Electric

When your power infrastructure project spans continents, reliability isn’t optional—it’s essential.

TSTY Electric brings 30 years of expertise to the table, delivering oil immersed transformers, dry type transformers, compact substations, and energy storage systems that perform in the world’s toughest environments—from 70°C desert heat to -40°C arctic cold.

What sets us apart?

Global compliance with IEC, CE, SGS standards

25,000㎡ smart factory with 25000 units annual capacity

80+ countries served, with local agent support in key markets

Whether you’re developing a solar farm, industrial grid, or rural electrification project, TSTY delivers zero-risk, high-return power solutions.