EN IEC/IEEE 60076-57-1202:2025/A11:2025

Overview

The EN IEC/IEEE 60076-57-1202:2025/A11:2025 standard is an important European amendment focused on liquid immersed phase-shifting transformers. Specifically tailored for phase-shifting transformers that are oil-immersed, this standard complements the existing EN 60076 series by addressing the unique requirements particular to phase-shifting transformers. It explicitly excludes transformers with unregulated phase shift, ensuring precise guidance and technical requirements for regulated phase-shifting units immersed in insulating liquids.

Developed by CLC’s Technical Committee on Power Transformers (CLC/TC 14), this amendment integrates alterations to normative references, technical clauses, and testing procedures, aligning with international regulations and improving clarity on energy performance, insulation systems, and transport guidelines.

Key Topics

• Scope and Exclusions
  Focuses exclusively on phase-shifting transformers with regulated phase shift, omitting general power transformer requirements already covered in the EN 60076 series.

• Normative References and Harmonization
  Incorporates new European normative references such as EN 50708 series, which detail additional requirements for medium and large power transformers, ensuring compliance with updated regulatory frameworks.

• Technical Modifications

  • Transport procedures updated referencing CIGRE Technical Brochure 673, improving the handling and logistics of phase-shifting transformers.
  • Energy performance requirements mandated according to EN 50708-1-1 and related standards, promoting efficiency in transformer design.
  • Adjustments in descriptions for liquid insulation and preservation systems, clarifying the gas and liquid surge relay devices terminology, referring to EN IEC 60076-22-1.

• Testing and Performance
  Modifications include specific guidance on lightning impulse tests applied to multiple terminals simultaneously (LIMT), emphasizing that these classifications take precedence over IEC 60076-3, ensuring high reliability under transient conditions.

• Technical Annexes and Bibliography Updates
  Annex ZA lists updated normative references to align international publications with their corresponding European standards, enhancing accessibility and traceability. The bibliography now includes key CIGRE brochures and additional parts of EN IEC 60076 series related to transformer fittings and accessories.

Applications

This standard is essential for manufacturers, testing laboratories, and utility companies involved in the design, production, and maintenance of liquid immersed phase-shifting transformers. Key applications include:

• Grid load management: Controllers for active power flow and reactive power compensation through phase angle adjustment.
• Electric power transmission systems: Enabling optimized power transfer and improved network stability via phase shift regulation.
• Energy efficiency improvements: Ensuring transformers meet stringent energy performance criteria, reducing losses and operating costs.
• Transformer transport and installation: Providing clear guidelines to minimize damage during transportation and setup, improving lifecycle reliability.

By adhering to EN IEC/IEEE 60076-57-1202:2025/A11, stakeholders benefit from enhanced safety, performance, and interoperability of phase-shifting transformers within European and international power systems.

Related Standards

• EN 60076 series – General power transformer standards covering temperature rise, insulation levels, short circuit withstand capacity, and sound levels.
• EN 50708 series – Additional European requirements for medium and large power transformers focusing on design, performance, and safety.
• EN IEC 60076-22 series – Standards concerning fittings and protective devices for power transformers, including gas relays and cooling systems.
• IEC 60214-1 – Performance requirements and test methods for tap-changers, closely related to phase-shifting transformer regulation mechanisms.
• CIGRE Technical Brochure 673 – Expert guidance on the transportation of large power transformers, referenced for safe handling practices.

These standards collectively enable a comprehensive framework for the development, testing, and operational guidance of liquid immersed phase-shifting transformers, ensuring consistent quality and adherence to best practices.

For more detailed information on the EN IEC/IEEE 60076-57-1202:2025/A11:2025, stakeholders should consult the full CENELEC publication and the related European and IEC standards referenced therein. This ensures compliance with the latest regulatory and technical requirements for power transformer applications.