A major milestone achieved in our 33kV transformer manufacturing journey!
Today marks a significant step forward for our ST20 13/20MVA 33/11kV Dyn11 transformer, developed for one of our DNO customers. After months of engineering, coordination and preparation, the unit has successfully completed its short circuit withstand testing in accordance with IEC 60076‑5, witnessed by our customers appointed consultant and carried out at an independent ISO/IEC 17025‑accredited laboratory at KEMA Labs.
This stage of the process is one of the most demanding and technically critical milestones in any transformer’s lifecycle. It involves far more than the short circuit impulses themselves, the full sequence includes pre and post routine testing, FRA comparisons, lightning impulse testing, de-tanking inspections and verification steps to confirm the unit’s mechanical integrity under extreme electromagnetic forces. It is a true testament to both design strength and manufacturing quality, and we’re pleased to see the unit perform exactly as intended.
With this phase now complete, the project moves into its final stage. The transformer will be transported back to our UK factory, where our engineering and production teams will carry out the following steps in the presence of customer and independent inspector:
– De‑tanking and detailed internal inspection
– Re‑assembly and re‑tank operations
– A second Factory Acceptance Test (FAT)
– Final verification for full customer approval
This return to factory phase is just as important as the short circuit testing itself, it allows us to demonstrate transparently that the active part has withstood the dynamic forces of the test, and that the unit remains mechanically sound and operationally ready before entering service.
A big thank you to everyone involved. All collaboration and oversight ensured a smooth, efficient and well documented testing process.
We now look forward to welcoming the unit back into our UK facility and completing the final FAT to officially conclude this transformers approval journey. Another proud moment for the team, and another strong example of Winder Power’s capability in delivering high reliability transformers for the UK network.
More updates to follow as we move into the final approval phase.
