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Our Factory
A State Grid Qualified Supplier Since 1979
Located in Changzhou, China, Guanghui Transformer operates a modern manufacturing base spanning 120 acres. With over four decades of industry expertise, we are an AAA Credit Enterprise and a National High-Tech Enterprise, dedicated to delivering reliable, efficient, and safe power transformer solutions to customers worldwide. Changzhou Guanghui Transformer Manufacturing Co., Ltd. was founded in 1979 and is located in Changzhou, a historic and culturally rich city in China with a well-developed industrial economy.
  • ● Photovoltaic & Wind Power Transformer

  • ● Industrial Isolation Transformer

  • ● Rectifier Transformer

  • ● Explosion-Proof Mining Transformer

Learn More About Us

Explore Our Products

Delivering specialized transformers for Urban Grids, Renewables, Mining, and EV Infrastructure. Engineered for stability in any sector.

Oil-Immersed Transformers

img of 300kva Fully Sealed Oil Immersed Transformer
300kva Fully Sealed Oil Immersed Transformer

The 300kva oil immersed transformer is a core piece of equipment for small and medium-capacity power distribution. Utilizing high-quality transformer oil as the insulation and cooling medium, it features stable heat dissipation and robust overload capabilities. Our 300kva oil immersed transformer is ideal for outdoor small substations, SME industrial parks, rural grid upgrades, and flexible installation scenarios requiring reliable power.

Core Parameters:

• Energy Efficiency: Tier 2 Efficiency (Complies with GB 20052-2024).

• Maintenance: Periodic Maintenance Design.

• Warranty: 3-Year Standard Warranty.


img of 500kVA Oil-Immersed Transformer (S13-500/10)
500kVA Oil-Immersed Transformer (S13-500/10)

The 500 kva oil filled transformer is a core piece of equipment for medium-capacity power distribution. Utilizing high-quality transformer oil as the insulation and cooling medium, it features excellent heat dissipation performance and stable overload capabilities. This 500 kva oil filled transformer is suitable for outdoor substations, medium-sized industrial park power distribution, urban distribution network upgrades, large commercial complexes, and medium-sized industrial enterprises that have higher requirements for power supply stability and medium power loads. It can operate stably for a long time in complex climatic environments ranging from -30℃ to 40℃, meeting the needs of medium-scale power transmission and distribution.

Core Parameters:

• Energy Efficiency: Tier 2 Efficiency (Complies with GB 20052-2024 "Minimum Allowable Values of Energy Efficiency and Energy Efficiency Grades for Power Transformers").

• Maintenance Features: Periodic Maintenance Design (requires periodic testing of transformer oil quality and sealing performance to extend equipment service life).

• Warranty Period: 3-Year Warranty (covers fault repair and replacement of core components, safeguarding users' long-term usage rights).


img of Single-Phase Transformer (10kVA - 500kVA)
Single-Phase Transformer (10kVA - 500kVA)

Our single-phase transformers are designed for standard step-down and step-up voltage conversions. Available in both dry-type and oil-immersed configurations, they are widely applicable for industrial and civil isolation and decentralized power distribution scenarios.


Core Parameters:

• Phase / Frequency: Single-phase / 50Hz

• Capacity Range: 10kVA - 500kVA

• Vector Group: I/I0

img of Three-Phase Wound Core Transformer (S13-M.RL Series)
Three-Phase Wound Core Transformer (S13-M.RL Series)

The S13-M.RL series utilizes an innovative 3D triangular wound core design. Constructed from high magnetic grain-oriented silicon steel with a jointless structure and vacuum annealed processing, it significantly enhances energy efficiency. It drastically lowers no-load loss, current, and operating noise compared to traditional laminated core models.


Core Parameters:

• Rated Voltage: 10kV±5% / 0.4kV

• Capacity Range: 30kVA - 2500kVA

• Vector Group: Dyn11 (Standard)

Dry-Type Transformers

img of 11kV Cast-Resin Dry-Type Transformer (SCB13 Series)
11kV Cast-Resin Dry-Type Transformer (SCB13 Series)

The 11kV cast-resin dry-type transformer is a core equipment for medium-voltage distribution systems. Utilizing a vacuum-cast epoxy resin insulation and air convection cooling design, it combines the benefits of being oil-free, eco-friendly, and highly flame-retardant with exceptional electrical stability. It is perfectly suited for 11kV distribution scenarios with strict safety requirements, such as industrial parks, commercial complexes, large hospitals, data centers, and high-precision manufacturing plants. Capable of operating reliably in standard climates (-25℃ to 40℃), it effectively meets the transmission and distribution needs of medium-capacity systems.

Core Parameters:

• Energy Efficiency: Tier 2 Efficiency (Complies with GB 20052-2024).

• Structure: Resin Cast Insulation + Air Convection Cooling (Fully enclosed, dustproof, moisture-proof).

• Warranty: 3-Year Standard Warranty.


img of 35kV Cast-Resin Dry-Type Transformer(SCB13 Series)
35kV Cast-Resin Dry-Type Transformer(SCB13 Series)

Our 35kV dry-type transformers feature capacities ranging from 30kVA to 5000kVA. Utilizing epoxy resin casting, the SCB13 series is currently one of the most widely used energy-saving products for 35kV voltage grades. They ensure high safety, excellent environmental adaptability, and full compliance with the latest efficiency standards.


Core Parameters:

• Voltage Ratings: 35kV / 0.4kV (Customizable)

• Insulation Class: Class F (155℃) or Class H (180℃)

• Cooling Method: AN / AF

New Energy & Compact Substation

img of 11kV 1000kVA Compact Substation
11kV 1000kVA Compact Substation

11kV/0.4kV, 1000kVA, Dyn11 connection, fully sealed and maintenance-free, compliant with IEC 60076 / ANSI standards.

The 11kV 1000kVA compact substation is a factory-prefabricated, integrated outdoor packaged power distribution unit. It integrates high-voltage switchgear, a distribution transformer, low-voltage distribution panels, and protection and control systems into one or more enclosed housings. Featuring a compact structure, small footprint, fast installation, reliable operation, and maintenance-free performance, it is widely used in urban power grids, industrial parks, residential communities, commercial buildings, new energy power stations, and infrastructure projects.

Compact size, with only one-tenth of the footprint of a conventional substation

Leak-proof oil design and maintenance-free operation

Zero-maintenance design

3-year warranty


img of 33kV 500kVA Compact Substation
33kV 500kVA Compact Substation

This compact packaged substation integrates high-voltage distribution, transformer step-down, and low-voltage distribution functions. It has a small footprint and is well suited for urban grid expansion and upgrading projects as well as power distribution in industrial parks.

The 33kV 500kVA compact substation is a factory-prefabricated, integrated outdoor packaged power distribution unit designed for medium- and high-voltage distribution applications. It integrates 33kV high-voltage switchgear, an oil-immersed distribution transformer, low-voltage distribution equipment, protection and control systems, and auxiliary devices inside an enclosed housing, delivering the core advantage of “factory pre-assembly and rapid on-site commissioning.


IP54 protection rating

Stable operation in complex outdoor climates

Zero-maintenance design

3-year warranty


Specialty Transformers

img of Traction Transformer (Railway & Urban Transit)
Traction Transformer (Railway & Urban Transit)

The traction transformer is a highly specialized core equipment designed exclusively for electrified railways (high-speed rail, bullet trains, standard rail) and urban transit systems (subway, light rail). Its primary function is to step down high-voltage grid power (110kV/220kV) to the precise voltage required by electric locomotives (27.5kV/55kV). Beyond voltage conversion, it achieves critical electrical isolation, phase transformation, and dynamic three-phase grid load balancing. Built to endure extreme, frequent short-circuit impacts and massive short-term overloads, it is the beating heart of modern transportation infrastructure.

Core Parameters:

• Rated Capacity: 10MVA ~ 63MVA (Supports 1.5x~2.0x short-term massive overload).

• Voltage Configuration: Grid side 110kV/220kV stepped down to Traction side 27.5kV/55kV.

• Special Vector Groups: V/v, Scott, YNvd, YNd11 optimized for transit load balancing.


img of Rectifier Transformer (Industrial DC Power Hub)
Rectifier Transformer (Industrial DC Power Hub)

The rectifier transformer is a heavy-duty special transformer engineered specifically to supply power to rectifying equipment (thyristors, diodes). Its primary function is to transform high or medium AC grid voltage into the precise AC voltage required by rectifier circuits to produce stable DC power. Furthermore, it achieves vital galvanic isolation, suppresses harmonic pollution via multi-pulse phase shifting, and aggressively resists DC bias saturation. It is the indispensable power source for electrolysis, electroplating, massive DC drives, and high-power charging systems.

Core Parameters:

• Rated Capacity: 100kVA ~ 100MVA (Built to endure 1.2x~1.5x severe load impacts).

• Voltage Configuration: Grid side 10kV/35kV stepped down to precise operational LV (tens to hundreds of Volts).

• Special Vector Groups: Phase-shifting designs (e.g., 12-pulse, 24-pulse) for harmonic elimination.


img of 35kV Cast-Resin Dry-Type Transformer(SCB13 Series)
35kV Cast-Resin Dry-Type Transformer(SCB13 Series)

Our 35kV dry-type transformers feature capacities ranging from 30kVA to 5000kVA. Utilizing epoxy resin casting, the SCB13 series is currently one of the most widely used energy-saving products for 35kV voltage grades. They ensure high safety, excellent environmental adaptability, and full compliance with the latest efficiency standards.


Core Parameters:

• Voltage Ratings: 35kV / 0.4kV (Customizable)

• Insulation Class: Class F (155℃) or Class H (180℃)

• Cooling Method: AN / AF

img of Three-Phase Wound Core Transformer (S13-M.RL Series)
Three-Phase Wound Core Transformer (S13-M.RL Series)

The S13-M.RL series utilizes an innovative 3D triangular wound core design. Constructed from high magnetic grain-oriented silicon steel with a jointless structure and vacuum annealed processing, it significantly enhances energy efficiency. It drastically lowers no-load loss, current, and operating noise compared to traditional laminated core models.


Core Parameters:

• Rated Voltage: 10kV±5% / 0.4kV

• Capacity Range: 30kVA - 2500kVA

• Vector Group: Dyn11 (Standard)

img of Single-Phase Transformer (10kVA - 500kVA)
Single-Phase Transformer (10kVA - 500kVA)

Our single-phase transformers are designed for standard step-down and step-up voltage conversions. Available in both dry-type and oil-immersed configurations, they are widely applicable for industrial and civil isolation and decentralized power distribution scenarios.


Core Parameters:

• Phase / Frequency: Single-phase / 50Hz

• Capacity Range: 10kVA - 500kVA

• Vector Group: I/I0

img of 500kVA Oil-Immersed Transformer (S13-500/10)
500kVA Oil-Immersed Transformer (S13-500/10)

The 500 kva oil filled transformer is a core piece of equipment for medium-capacity power distribution. Utilizing high-quality transformer oil as the insulation and cooling medium, it features excellent heat dissipation performance and stable overload capabilities. This 500 kva oil filled transformer is suitable for outdoor substations, medium-sized industrial park power distribution, urban distribution network upgrades, large commercial complexes, and medium-sized industrial enterprises that have higher requirements for power supply stability and medium power loads. It can operate stably for a long time in complex climatic environments ranging from -30℃ to 40℃, meeting the needs of medium-scale power transmission and distribution.

Core Parameters:

• Energy Efficiency: Tier 2 Efficiency (Complies with GB 20052-2024 "Minimum Allowable Values of Energy Efficiency and Energy Efficiency Grades for Power Transformers").

• Maintenance Features: Periodic Maintenance Design (requires periodic testing of transformer oil quality and sealing performance to extend equipment service life).

• Warranty Period: 3-Year Warranty (covers fault repair and replacement of core components, safeguarding users' long-term usage rights).


img of 300kva Fully Sealed Oil Immersed Transformer
300kva Fully Sealed Oil Immersed Transformer

The 300kva oil immersed transformer is a core piece of equipment for small and medium-capacity power distribution. Utilizing high-quality transformer oil as the insulation and cooling medium, it features stable heat dissipation and robust overload capabilities. Our 300kva oil immersed transformer is ideal for outdoor small substations, SME industrial parks, rural grid upgrades, and flexible installation scenarios requiring reliable power.

Core Parameters:

• Energy Efficiency: Tier 2 Efficiency (Complies with GB 20052-2024).

• Maintenance: Periodic Maintenance Design.

• Warranty: 3-Year Standard Warranty.


img of Rectifier Transformer (Industrial DC Power Hub)
Rectifier Transformer (Industrial DC Power Hub)

The rectifier transformer is a heavy-duty special transformer engineered specifically to supply power to rectifying equipment (thyristors, diodes). Its primary function is to transform high or medium AC grid voltage into the precise AC voltage required by rectifier circuits to produce stable DC power. Furthermore, it achieves vital galvanic isolation, suppresses harmonic pollution via multi-pulse phase shifting, and aggressively resists DC bias saturation. It is the indispensable power source for electrolysis, electroplating, massive DC drives, and high-power charging systems.

Core Parameters:

• Rated Capacity: 100kVA ~ 100MVA (Built to endure 1.2x~1.5x severe load impacts).

• Voltage Configuration: Grid side 10kV/35kV stepped down to precise operational LV (tens to hundreds of Volts).

• Special Vector Groups: Phase-shifting designs (e.g., 12-pulse, 24-pulse) for harmonic elimination.


img of Traction Transformer (Railway & Urban Transit)
Traction Transformer (Railway & Urban Transit)

The traction transformer is a highly specialized core equipment designed exclusively for electrified railways (high-speed rail, bullet trains, standard rail) and urban transit systems (subway, light rail). Its primary function is to step down high-voltage grid power (110kV/220kV) to the precise voltage required by electric locomotives (27.5kV/55kV). Beyond voltage conversion, it achieves critical electrical isolation, phase transformation, and dynamic three-phase grid load balancing. Built to endure extreme, frequent short-circuit impacts and massive short-term overloads, it is the beating heart of modern transportation infrastructure.

Core Parameters:

• Rated Capacity: 10MVA ~ 63MVA (Supports 1.5x~2.0x short-term massive overload).

• Voltage Configuration: Grid side 110kV/220kV stepped down to Traction side 27.5kV/55kV.

• Special Vector Groups: V/v, Scott, YNvd, YNd11 optimized for transit load balancing.


img of 33kV 500kVA Compact Substation
33kV 500kVA Compact Substation

This compact packaged substation integrates high-voltage distribution, transformer step-down, and low-voltage distribution functions. It has a small footprint and is well suited for urban grid expansion and upgrading projects as well as power distribution in industrial parks.

The 33kV 500kVA compact substation is a factory-prefabricated, integrated outdoor packaged power distribution unit designed for medium- and high-voltage distribution applications. It integrates 33kV high-voltage switchgear, an oil-immersed distribution transformer, low-voltage distribution equipment, protection and control systems, and auxiliary devices inside an enclosed housing, delivering the core advantage of “factory pre-assembly and rapid on-site commissioning.


IP54 protection rating

Stable operation in complex outdoor climates

Zero-maintenance design

3-year warranty


img of 11kV 1000kVA Compact Substation
11kV 1000kVA Compact Substation

11kV/0.4kV, 1000kVA, Dyn11 connection, fully sealed and maintenance-free, compliant with IEC 60076 / ANSI standards.

The 11kV 1000kVA compact substation is a factory-prefabricated, integrated outdoor packaged power distribution unit. It integrates high-voltage switchgear, a distribution transformer, low-voltage distribution panels, and protection and control systems into one or more enclosed housings. Featuring a compact structure, small footprint, fast installation, reliable operation, and maintenance-free performance, it is widely used in urban power grids, industrial parks, residential communities, commercial buildings, new energy power stations, and infrastructure projects.

Compact size, with only one-tenth of the footprint of a conventional substation

Leak-proof oil design and maintenance-free operation

Zero-maintenance design

3-year warranty


img of 11kV Cast-Resin Dry-Type Transformer (SCB13 Series)
11kV Cast-Resin Dry-Type Transformer (SCB13 Series)

The 11kV cast-resin dry-type transformer is a core equipment for medium-voltage distribution systems. Utilizing a vacuum-cast epoxy resin insulation and air convection cooling design, it combines the benefits of being oil-free, eco-friendly, and highly flame-retardant with exceptional electrical stability. It is perfectly suited for 11kV distribution scenarios with strict safety requirements, such as industrial parks, commercial complexes, large hospitals, data centers, and high-precision manufacturing plants. Capable of operating reliably in standard climates (-25℃ to 40℃), it effectively meets the transmission and distribution needs of medium-capacity systems.

Core Parameters:

• Energy Efficiency: Tier 2 Efficiency (Complies with GB 20052-2024).

• Structure: Resin Cast Insulation + Air Convection Cooling (Fully enclosed, dustproof, moisture-proof).

• Warranty: 3-Year Standard Warranty.


Comprehensive Power Solutions for Key Industries

Delivering specialized transformers for Urban Grids, Renewables, Mining, and EV Infrastructure. Engineered for stability in any sector.
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Renewable Energy

The design emphasizes low loss, resilience to harsh wind farm environments, and adaptability to fluctuating wind power loads.
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EV Charging Infrastructure

Our transformers offer wide load regulation to handle large peak–valley differences, concentrated loads, and high instantaneous power, minimizing light-load losses and overload risks.
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Utility & Grid

From high-density urban areas to aging neighborhoods, high-protection enclosures with intelligent temperature control withstand heavy loads, humidity, and electromagnetic interference.
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Industrial & Mining

Matched to the high energy demands of high-altitude mines, the low-loss design reduces power losses and directly supports overall operating cost control.
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Globally Trusted High-Efficiency Transformers
  • 01.
    adv_dsdq_icon_1
    Precision Core Cutting & Vacuum Casting Excellence
    German advanced manufacturing technology featuring TechGeorg precision core cutting and Hübers state-of-the-art vacuum casting processes for superior quality and reliability.
  • 02.
    adv_dsdq_icon_2
    Durable Tanks Engineered for Reliability
    Robust and durable tank design featuring high-quality sealing solutions and precision welding techniques to ensure long-lasting performance and reliability under demanding conditions.
  • 03.
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    Global Custom Voltage & Frequency Solutions
    Global customization capabilities offering tailor-made voltage options ranging from 6 to 35kV and flexible frequency settings of 50 or 60Hz to meet diverse international requirements and specific customer needs.
  • 04.
    adv_dsdq_icon_4
    Custom Engineered Transformers
    Engineered for the unique. From special frequencies (400Hz+) to IP66 enclosures, we build solutions for non-standard voltages and extreme environments where off-the-shelf fails.
80,000
The company covers an area of 80000 square meters
20+
20 transformer production lines
15
Including 15 complete sets of high and low voltage production lines
80+
Exported to over 80 countries worldwide
200+
An average daily production capacity of more than 200 units
Guanghui: Global Market Leader for Transformer Manufacturing
background image of Guanghui: Global Market Leader for Transformer Manufacturing
We operate on a factory area of over
80000
Square meters
Capable of meeting large-scale production orders.
We have over
40
Years
Our company has grown into a trusted transformer manufacturer
We have over
100
Engineers
In production, development, sales, service, and support.
In more than
80
Countries
We possess rich expertise in international trade.

Successful Projects

Group Private Customization Project

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Jiangsu Canqin Technology Co., Ltd.

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Huazhong Precision Technology (Ma'anshan) Co., Ltd.

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Changzhou Vocational Institute of Textile and Garment

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Yanyi Railway Tunne

Engineered for Reliability
Backed by advanced equipment, rigorous processes, and decades of expertise, Guanghui Transformer ensures superior quality and reliability at every stage of manufacturing—from core precision and vacuum casting to comprehensive testing.
icon of Precision Core Technology
Precision Core Technology
Georg step-lap lines ensure industry-leading efficiency, reduced core losses, and consistently low operating noise levels.
icon of Advanced Vacuum Process
Advanced Vacuum Process
Vacuum casting & filling eliminates voids, ensuring superior insulation strength, long-term reliability, and stable performance.
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Certified Quality Lab
100% IEC/ANSI compliance testing is performed before every shipment to ensure safety, reliability, and consistent product quality.
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Tell us your specs (Voltage, kVA, Application). Our engineers will design a solution compliant with international standards.

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