The EU eco-design Tier 2 regulations impose strict energy efficiency limits on transformers sold in the EU. Many parts suppliers and photovoltaic EPC engineering parties only simply modified the parameters on the drawings, and the final product could not pass the compliance inspection, resulting in container delays and delays in on-site commissioning of the project. The complete set of actual design adjustments from the iron core to the factory test is the key to meeting Tier 2.
Design Adjustments
Core material selection
Low-loss oriented silicon steel is the foundation. Ordinary grades of silicon steel do not reach the no-load loss threshold of Tier 2. Actual project experience shows that thin-specification, high-permeability iron cores are selected, and the stacking process is optimized to minimize the internal air gap. Even if the position of the iron core seam is slightly improved, the eddy current loss generated during operation can be effectively reduced.
Optimization of winding structure
Tier 2 has strict constraints on load loss.In the actual project, we will appropriately increase the cross-section of the conductor and use transposition wires to reduce stray losses. Both oil-immersed and dry-type transformers need to arrange their windings reasonably to suppress magnetic leakage. Simply amplifying the cross-section of the wire cannot solve all the problems. Local hot spots will occur if the winding arrangement is unreasonable, and the long-term operation life of the equipment on site will be damaged.
Cooling system matching
The cooling effect and loss control complement each other. ONAN oil-immersed self-cooling and forced air-cooling schemes must recalculate the heat budget. When the cooling margin is insufficient, the continuous high temperature will accelerate the aging of the insulation, even if the laboratory loss data is up to standard, it is of no practical significance. For some high-humidity working conditions in Europe, dry transformers should also focus on the layout of the air ducts in the cabinet.
Insulation and temperature rise check
The insulation level must match the actual hot spot temperature. Tier 2 compliance does not only look at the loss index, the type test report needs to retain the temperature rise test data in its entirety. We have been in contact with real projects and passed the transformer loss test, but the temperature rise exceeded the standard and was directly rejected, and all the ecological design certification documents were invalid.
Production tolerance and pre-factory test verification
There will always be deviations between the theoretical calculations of drawings and the physical finished products. It is critical to strictly control the manufacturing tolerances of iron core laminations and windings. Be sure to complete sample pre-testing before mass production, and do not do Tier 2 formal certification after mass production. Early sample investigation can identify hidden defects and avoid the risk of high rework and even product recall.
One-stop Electric Equipment Factory in China
In general, meeting the EU Tier 2 is a complete set of system-level design changes, not simply adjusting a few parameters. In the early stage of the project, the iron core, winding, cooling, and test verification must be considered simultaneously. Cooperation with factories with practical Ecodesign testing experience can help European photovoltaic and industrial projects avoid economic losses caused by compliance.
