IEC 60071-1:2019

Overview

IEC 60071-1:2019, published by the International Electrotechnical Commission (IEC), establishes the fundamental definitions, principles, and rules for insulation co-ordination in three-phase AC systems with a highest voltage for equipment above 1 kV. This standard specifies procedures for selecting rated withstand voltages for phase-to-earth, phase-to-phase, and longitudinal insulation in high-voltage equipment and installations. By providing lists of standard withstand voltages, IEC 60071-1 serves as a horizontal standard and reference for various equipment standards to support consistent and safe electrical infrastructure design. It is not intended to address human safety directly but focuses on the proper dielectric coordination to assure reliable system performance.

Key Topics

• Insulation Co-ordination Principles: IEC 60071-1 outlines how to relate dielectric strength requirements of equipment to the characteristic voltages and overvoltages present in a power system. The standard considers service environments and the operational exposure of the insulation.

• Rated Withstand Voltages: Procedures for selecting appropriate withstand voltages, including phase-to-earth, phase-to-phase, and longitudinal insulation, to ensure equipment reliability.

• Standard Withstand Voltage Values: Provides standard values for short-duration power frequency, switching impulse, and lightning impulse tests. These values enable uniformity across the industry and facilitate international trade.

• Definitions and Terminology: Contains clear definitions for key terms such as insulation co-ordination, external and internal insulation, withstand voltage, and standard insulation levels, supporting clear communication and application among technical professionals.

• Selection Procedures: Describes the steps for associating selected withstand voltages with the highest voltage for the equipment, relevant only for insulation co-ordination purposes, not for human safety.

• Testing Requirements: Details the basic requirements for standard withstand voltage tests, including the necessary conditions, methods, and references to related IEC standards for test implementation.

• Updates and Revisions: The 2019 edition features updated references, clarifies terminology, harmonizes letter symbols with related IEC documents, and makes editorial improvements for better understanding.

Applications

The practical value of IEC 60071-1:2019 is in supporting the design, specification, and testing of high-voltage equipment and installations in power transmission and distribution networks. It is widely used by:

• Equipment Designers and Manufacturers: To select appropriate insulation levels for new products and ensure compliance with international standards.

• Utility Engineers and System Planners: For specifying reliable insulation levels in substation and transmission projects, reducing the risk of insulation failure and subsequent system outages.

• Standards Developers: As a horizontal standard, IEC 60071-1 provides foundational principles referenced by other IEC standards for specific equipment types.

• Test Laboratories: For conducting standardized dielectric tests on high-voltage equipment, ensuring consistency and comparability across products.

• Regulatory Bodies: To harmonize regional or national standards with widely accepted international practices, facilitating interoperability and global market access.

Related Standards

• IEC 60071-2: Application guide providing justifications and practical guidance for rules established in IEC 60071-1, particularly regarding the association of standard withstand voltages with the maximum equipment voltage.

• IEC 60038: Standard voltages, referenced for uniform voltage classification.

• IEC 60060-1: High-voltage test techniques, specifying general definitions and test requirements.

• IEC 60099-4: Surge arresters specification, relevant for overvoltage protection in AC systems.

• IEC 60507: Artificial pollution tests on high-voltage insulators, addressing environmental factors impacting insulation performance.

• IEC 60633: Terminology for high-voltage direct current (HVDC) transmission, supporting consistency in definitions.

By adhering to IEC 60071-1:2019, organizations contribute to the reliability, safety, and longevity of power systems and high-voltage equipment globally, promoting best practices in insulation co-ordination.