Split-Winding Power Transformer for an Energy Storage Project in Greece

Hybrid renewable energy facilities introduce more complex operating cycles and dynamic grid-support requirements for modern power systems. This project required a high-voltage power transformer with proven operational reliability, flexibility for multi-bus applications, and full compliance with stringent European standards.

The integration of photovoltaic generation and energy storage through a single transformer also required a customized split-winding configuration, robust short-circuit structural design, and effective thermal and acoustic management. Advanced design technologies, structural engineering, and optimized manufacturing workflows were integrated to deliver a fully verified, customized power transformer solution within an accelerated project schedule.

• Dual-source system integration — Integrating distinct renewable energy generation and energy storage assets through a single transformer required robust electrical decoupling to accommodate fluctuating power flows while minimizing mutual fault interference.

• Thermal and Eco-Design requirements — The transformer had to comply with European Eco-Design requirements and acoustic noise limits while managing harmonic heating and severe thermal cycling caused by fluctuating renewable power flows.

• Short-circuit mechanical stress — Compared with standard two-winding designs, the split-winding configuration experiences highly unbalanced electromagnetic forces under fault conditions, placing higher demands on mechanical stability and short-circuit withstand capability.

• Custom split-winding configuration — A specialized split-winding layout was engineered on a single core to provide robust electrical decoupling and the required branch impedance between the renewable energy and energy storage systems without requiring multiple transformers.

• High-efficiency and thermal design — Advanced design software, automated production lines, and multi-stage quality verification were utilized to control acoustic emissions and optimize cooling channels, meeting applicable European Eco-Design requirements.

• Reinforced short-circuit structural stability — Dynamic electromagnetic forces were modeled using 3D simulation tools, and the windings were reinforced with rigid axial clamping to maintain structural integrity and meet short-circuit testing requirements.

• Integrated multi-winding architecture — The transformer combines two electrically decoupled split windings with a tertiary delta winding for harmonic current circulation on a single core, replacing multiple standalone transformers while utilizing directed cooling channels to control localized hot spots and winding temperature rise.

• Short-circuit withstand and testing — The transformer was designed in accordance with IEC and European Eco-Design requirements and validated through dynamic short-circuit withstand, temperature-rise testing, loss measurement, and sound level testing.

• Cyclic and inverter-duty performance — The transformer is engineered for multi-cycle daily dispatch under severe harmonic loading, supporting uninterrupted full-load operation while safeguarding winding insulation against dynamic thermal and mechanical stress.