• Product advantages
• Product parameters
• Ordering instructions

Product advantages

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66kv Power Transformer Technical Standards & Global Certifications

To guarantee seamless integration into international power markets, our 66kV power transformers are engineered and tested according to global benchmarks:

- International Standards: Fully compliant with GB, IEC, GOST, EN, NF, and ANSI/IEEE. Custom engineering is available to match your local utility grid codes.

- Product Certifications: Certified by ISO, CE, IEC, SABS, COC, CSA, and UL, ensuring world-class safety, quality, and performance.
 

Key 66kv Power Transformer Advantages

- Proven Grid Stability: Validated by extensive operational data across complex working conditions, including harsh climates and fluctuating renewable energy loads.

- Eco-Friendly & Sustainable: Available with FR3 natural ester bio-degradable insulation oil and highly recyclable components. This drastically reduces the carbon footprint and aligns with international "Dual Carbon" and ESG initiatives.

- Global Footprint: Trusted and running in over 50 countries and regions, bridging power gaps in high-demand markets across India, Nepal, Malaysia, Kazakhstan, Uzbekistan, Tanzania, Kenya, Mozambique and more

Why Choose Hengfengshuai Electric for Your 66kV Projects?

When investing in critical high-voltage infrastructure, choosing the right manufacturing partner is as vital as the equipment itself. Here is why global EPC contractors and utilities partner with Hengfengshuai Electric:

Tier-1 Engineering & Customized R&D

At Hengfengshuai Electric, we don't believe in one-size-fits-all. Our technical team tailors every 66kV transformer to your specific environmental constraints—whether it’s high altitude, extreme ambient temperatures, or highly corrosive industrial zones.

Unmatched Delivery Speed (Industry-Leading 50-Day Turnaround)

In an industry where lead times often span 6 to 12 months, Hengfengshuai Electric leverages an agile, fully integrated supply chain to deliver your 66kV main transformer in as little as 50 days, significantly cutting your project’s time-to-market.

Rigorous Quality Control & Zero-Defect Testing

Every unit undergoes exhaustive factory acceptance testing (FAT) in our state-of-the-art high-voltage laboratories. From impulse voltage tests to partial discharge detection, we ensure your transformer arrives ready for seamless commissioning.

Global Service & Lifecycle Support

From initial layout design and international logistics to on-site installation guidance and post-warranty maintenance, Hengfengshuai Electric provides 24/7 technical support, ensuring your substation operates at peak performance for decades.

Product parameters

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Rated capacity	Voltage Ratio	Vector Group	Cooling method	Short circuit impedance
5000	35/6.3,35/10.5,33/11.5 ,33/6.9	Yd11	ONAN/ONAF	0.065
6300	35/6.3,35/10.5,33/11.5 ,33/6.9	Yd11	ONAN/ONAF	0.065
8000	35/6.3,35/10.5,33/11.5 ,33/6.9	Yd11	ONAN/ONAF	0.065
10000	35/6.3,35/10.5,33/11.5 ,33/6.9	Dy11	ONAN/ONAF	0.065
25000	66/13.8,66/11.5,66/21	Dyn11	ONAN/ONAF	0.075
31500	110/10.5,110/11.5,110/13.8,110/21	YNd11	ONAN/ONAF	0.105
40000	110/10.5,110/11.5,110/13.8,110/21	YNyn0d11	ONAN/ONAF	0.105
50000	110/10.5,110/11.5,110/13.8,110/21	YNd11	ONAN/ONAF/ODAF	0.17
63000	110/10.5,110/11.5,110/13.8,110/21	YNd11	ONAN/ONAF/ODAF	0.17

   

Rated capacity	Voltage Ratio	Vector Group	Cooling method	Short circuit impedance
5000	35/6.3,35/10.5,33/11.5 ,33/6.9	Yd11	ONAN/ONAF	0.065
6300	35/6.3,35/10.5,33/11.5 ,33/6.9	Yd11	ONAN/ONAF	0.065
8000	35/6.3,35/10.5,33/11.5 ,33/6.9	Yd11	ONAN/ONAF	0.065
10000	35/6.3,35/10.5,33/11.5 ,33/6.9	Dy11	ONAN/ONAF	0.065
25000	66/13.8,66/11.5,66/21	Dyn11	ONAN/ONAF	0.075
31500	132/10.5,110/11.5,110/13.8,110/21	YNd11	ONAN/ONAF	0.105
40000	132/10.5,110/11.5,110/13.8,110/21	YNyn0d11	ONAN/ONAF	0.105
50000	132/10.5,110/11.5,110/13.8,110/21	YNd11	ONAN/ONAF/ODAF	0.17
63000	132/10.5,110/11.5,110/13.8,110/21	YNd11	ONAN/ONAF/ODAF	0.17

Ordering instructions

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- Main parameters of transformer (voltage, capacity, loss and other main parameters)
- Transformer operating environment (altitude, temperature, humidity, location, etc.)
- Other customization requirements (tap switch, color, oil pillow, etc.)
- The minimum order quantity is 1 sets
- Normal delivery period of 30 days, worldwide fast delivery