Solar power now accounts for the fastest-growing segment of new generation capacity worldwide, and the transformer requirements it creates span an unusually wide range of voltage levels, installation environments, and load profiles.
Hitachi Energy supplies transformer solutions for every stage of that chain, from the inverter interface at the point of generation through to the transmission network that carries bulk solar power across continents. Whether the project is a utility-scale ground-mounted array in a desert environment or a rooftop aggregation scheme feeding a substation, Hitachi Energy’s engineering and manufacturing capability covers the specification.
3.5 GWh
energy flow per year through our renewable power substations
>12.500
dry-type and liquid-filled transformers installed base
>4 GW
of capacity delivered with solutions for power conversion
1.5
million Tons CO2 saved per year
Power Conversion
At the point where solar and battery systems connect to inverters, transformers form part of the Power Conversion System (PCS: Power Block AC), converting power and stepping it up to medium voltage. This setup acts as a repeatable building block across solar and storage plants, allowing projects to scale efficiently.
Hitachi Energy supports this stage with a portfolio of dry-type and liquid-filled distribution transformers, designed to be potentially integrated into skid-mountedor containerized systems, enabling fast deployment and consistent performance across large installations.
Grid Connection
Beyond power conversion, transformers enable solar and storage plants to connect reliably to the grid across different voltage levels. Hitachi Energy’s grid connection portfolio spans both sub-transmission and transmission networks, supporting projects from regional connections to large utility-scale systems.
At the sub-transmission level, solutions such as Small Power Transformers are used to provide standardized and scalable connections to regional grids. At the transmission level, Medium and Large Power Transformers support larger, more complex projects connecting directly to high-voltage networks.
Battery Energy Storage (BESS)
Battery energy storage systems are supported within the same power conversion architecture, where transformers are integrated into standardized PCS units. These systems are widely used by OEMs, system integrators, and battery manufacturers, particularly in containerized and modular installations.
Hitachi Energy develops these solutions in close collaboration with customers, combining design validation, testing, and global production capabilities. Our transformer technologies are supporting safe and efficient integration into both standalone storage and combined solar-plus-storage projects.
Built for solar and storage
We enable reliable solar and storage operations from first power conversion to long-term grid performance.
Proven Technology
With more than 25 years of experience, our application-driven transformer technology combines deep grid expertise with proven reliability in even the harshest solar and storage environments.
Simplifying Complex Projects
We simplify complexity with a complete, qualified transformer portfolio from power conversion to grid connection, engineered specifically for solar PV and BESS operating conditions.
Sustainability and Safety by design
Designed with sustainability and safety at their core, our transformers support environmental impact reduction and enable more efficient, resilient energy infrastructure integration.
A Partner Across the Project Lifetime
We are your long-term project partner, delivering end-to-end lifecycle support and services while optimizing cost and performance across every stage of the asset lifecycle.
Scalable Footprint & Global Delivery
Our global manufacturing footprint and flexible supply network provide the responsiveness, scale, capacity, and delivery flexibility that fast-growing solar and storage markets demand.
Grid Expertise
Helping solar PV and BESS developers connect to the grid with confidence through advanced transformer solutions, proven utility-scale expertise, and compliance with evolving grid codes, technical specifications, and international standards.
Transformers Portfolio for Solar Power & BESS
- Power Conversion
- Grid Connection: Sub-transmission
- Grid Connection: Transmission
At the DC/AC interface, transformers operate as part of the Power Conversion System, where inverter-based conversion introduces operating conditions that differ from conventional grid applications. These include harmonic content, fast-switching behaviour, and cyclic loading, requiring transformer designs specifically adapted to inverter-driven loads.
Hitachi Energy’s power conversion transformers are developed for this duty, using application-specific and multi-winding designs rather than conventional utility-based configurations. Key design considerations include:
- Inverter-driven operation, with harmonics and fast switching from power electronics
- Cyclic loading profiles, requiring designs suited to repeated load variation
- Application-specific engineering, developed for inverter-based duty rather than conventional grid designs
- Flexible technologies, with dry-type and liquid-filled options depending on site and safety requirements
To support scalable deployment, these transformers are designed for integration into containerized and skid-mounted systems, enabling standardized, plug-and-play solutions across utility-scale solar, hybrid, and battery storage projects.
Customer Stories
Frequently Asked Questions (FAQs) about Transformers for Solar & BESS
Find quick answers to common questions about transformers for solar, their role in power systems, and how Hitachi Energy solutions deliver efficiency and reliability.
Solar and BESS applications create operating conditions that differ from conventional grid systems, including inverter harmonics, fast-switching power electronics, cyclic loading, and frequent thermal fluctuations. Transformers designed specifically for these conditions help ensure reliable performance and long asset life.
Solar and storage facilities connect to the grid through transformer-based substations operating at sub-transmission or transmission voltage levels. The specific solution depends on project size, grid requirements, and the voltage level of the point of interconnection.
Within a PCS, transformers step up voltage from the inverter output to medium-voltage levels suitable for collection networks and grid integration. They form a critical part of the power conversion architecture used across solar and battery energy storage facilities.
Hitachi Energy offers both dry-type and liquid-filled transformer technologies. The selection depends on project requirements such as environmental conditions, installation constraints, fire safety considerations, and operational performance objectives.
Yes. Hitachi Energy's transformer portfolio supports standalone solar, standalone battery energy storage, and integrated solar-plus-storage projects, providing solutions for power conversion, grid connection, and long-term operation across all configurations.
Something caught your eye?
Our sales team will get in touch with you