A power transformer transfers electrical energy between different voltage levels in transmission and distribution systems. Transformers are widely installed in substations, power plants, industrial facilities, renewable energy projects and utility networks. EnerStorAI supplies oil-immersed and dry-type power transformers from 50kVA to 500MVA+ with voltage classes up to 800kV, engineered to IEC and IEEE standards.
Technical Specifications
| Item | Specification |
|---|---|
| Rated Power | 50kVA – 500MVA+ |
| Voltage Class | 10kV – 800kV |
| Frequency | 50Hz / 60Hz |
| Cooling Method | ONAN, ONAF, OFAF, OFWF |
| Winding Material | Copper or Aluminum |
| Insulation Class | Oil-Immersed or Dry-Type |
| Vector Group | Dyn11, Yyn0, YNd11, Customized |
| Standards | IEC 60076, IEEE C57, ANSI |
Available Transformer Types
Oil-Immersed Power Transformer
Oil-immersed transformers use mineral oil or insulating fluid for cooling and electrical insulation. Applications: utility substations, power generation plants, industrial power systems and renewable energy projects. Features: high overload capability, efficient heat dissipation, suitable for outdoor installation, available up to extra-high voltage levels.
Dry-Type Transformer
Dry-type transformers use air or cast resin insulation and are commonly installed indoors. Applications: commercial buildings, hospitals, airports, data centers and high-rise buildings. Features: low maintenance, no oil leakage risk, suitable for indoor environments and enhanced fire safety performance.
Power Transformers for Battery Energy Storage Systems
Battery energy storage systems connect to the grid through step-up transformers that match the system voltage to the grid. A BESS transformer must handle bidirectional power flow, harmonic content from the PCS and rapid load changes. Typical configurations include:
- Distribution-class transformers (10-35kV) for C&I and containerized BESS.
- Unit transformers paired with the PCS for utility-scale storage plants.
- Compact pad-mounted or skid-mounted designs for space-constrained projects.
When selecting a transformer for a BESS project, confirm the vector group (Dyn11 is common for distribution), impedance, no-load and load losses, and the temperature rise limits. See our energy storage transformer page for details.
Typical Applications
Utility power networks: transformers installed in transmission and distribution substations convert voltage between generation, transmission and end-user systems. Renewable energy projects: voltage transformation for solar farms, wind power plants and battery energy storage systems. Industrial facilities: manufacturing plants, mining operations, petrochemical facilities and steel mills. Infrastructure projects: railways, airports, data centers and water treatment plants.
Key Components
Magnetic core, HV and LV windings, transformer tank, bushings, conservator, breather, radiators and tap changer.
Testing and Quality Control
Each transformer can be tested according to IEC and IEEE standards, including ratio test, insulation resistance test, no-load loss test, load loss test, temperature rise test, partial discharge test, and routine and type tests. Test reports are provided with every unit.
Custom Manufacturing
Available options include copper or aluminum windings, ONAN/ONAF cooling systems, low-loss core designs, low-noise configurations, offshore and desert environments, and custom voltage and MVA ratings. Technical datasheets and project-specific quotations are available on request.
Transformer Efficiency and Losses
Transformer losses fall into two categories. No-load (iron) losses run continuously whenever the transformer is energized, so they dominate the lifetime cost of lightly loaded units. Load (copper) losses increase with the square of the current and matter most for units that operate near rated capacity, such as BESS transformers cycling daily. Low-loss core designs and optimized winding configurations reduce both, improving the overall efficiency of your power plant or storage system.
When comparing quotes, ask for the guaranteed no-load and load loss values, impedance and temperature rise class, and evaluate them across the expected lifetime of the project – not just the purchase price.
BESS Transformer Selection Checklist
- Confirm the grid connection voltage, frequency (50Hz/60Hz) and earthing arrangement.
- Match the transformer rating to the PCS output and the expected charge/discharge overload profile.
- Select the vector group (Dyn11 is typical for distribution) and impedance for your protection scheme.
- Specify no-load loss, load loss and temperature rise class for lifetime efficiency.
- Choose the cooling method (ONAN, ONAF, OFAF) according to site conditions and duty cycle.
- Verify transport dimensions, noise limits and environmental requirements (desert, offshore, high altitude).
Our engineers prepare a transformer specification based on these inputs, including all routine and type test documentation, before production begins.
Why Choose EnerStorAI for Power Transformers
EnerStorAI combines factory-direct manufacturing with international standard compliance. Every transformer is designed to IEC 60076, IEEE C57 and ANSI, tested before shipment, and delivered with complete documentation. For energy storage projects, our engineers understand bidirectional loading, harmonic content and grid code requirements, so you receive a transformer matched to your PCS and application – not an off-the-shelf unit that merely “works”.
Installation, Commissioning and After-Sales Support
Every transformer ships with installation and commissioning documentation, including oil sampling guidance for oil-immersed units, earthing requirements, and pre-energization test procedures. EnerStorAI supports projects from specification to site commissioning, and our after-sales team provides spare parts, technical documentation and engineering support throughout the transformer’s service life.
Frequently Asked Questions
What is the difference between oil-immersed and dry-type transformers?
Oil-immersed transformers use insulating oil for cooling and insulation, offering high overload capability and suitability for outdoor and high-voltage applications. Dry-type transformers use air or cast resin, require minimal maintenance, have no oil leakage risk and are preferred for indoor and fire-sensitive environments.
What transformer is needed for a BESS project?
Most C&I and containerized BESS use distribution-class transformers at 10-35kV with a Dyn11 vector group. Utility-scale projects use unit transformers matched to the PCS output and grid code requirements.
Can you supply transformers for 60Hz markets?
Yes, we manufacture transformers for both 50Hz and 60Hz networks to the relevant local standards.
What standards do your transformers comply with?
Our transformers are designed and tested to IEC 60076, IEEE C57 and ANSI standards, with full test reports available for each unit.
How do I request a transformer quotation?
Provide your required MVA/kVA rating, primary and secondary voltages, vector group, ambient conditions and standard. Contact s18301170098@gmail.com or WhatsApp +86 18301170098.
Request a Power Transformer Quote
EnerStorAI supports complete power and storage projects with low voltage cables, energy storage transformers and commercial energy storage systems.
Email: s18301170098@gmail.com | WhatsApp: +86 18301170098 | WeChat: 18301170098
Power Transformer RFQ Information
For a transformer quotation, share rated kVA/MVA, primary and secondary voltage, frequency, vector group, impedance, cooling method, installation environment and required standard.
Request a quotation: Email s18301170098@gmail.com or WhatsApp +86 18301170098. Include your application, quantity and destination so the engineering team can recommend a configuration.