IEC 60071-2:1996

• Abstract:

  IEC 60071-2:1996 gives guidance for the determination of the rated withstand voltages for ranges I and II of IEC 60071-1 and justifies the association of these rated values with the standardized highest voltages for equipment. It covers phase-to-phase, phase-to-earth and longitudinal insulation of three-phase systems with nominal voltages above 1kV. It has the status of a horizontal standard in accordance with IEC Guide 108.

• Status: Published
• Publication Date: 18-Dec-1996
• ICS: 29.080.30 - Insulation systems
• Technical Committee: TC 28 - Insulation co-ordination
• Current Stage: DELPUB - Deleted Publication
• Start Date: 16-Mar-2018
• Completion Date: 28-Aug-2026

• Revised: IEC 60071-2:2018 - Insulation co-ordination - Part 2: Application guidelines
• Effective Date: 05-Sep-2023

Overview

IEC 60071-2:1996 – Insulation co-ordination – Part 2: Application guide, published by the International Electrotechnical Commission (IEC), is a foundational standard for the selection and application of insulation levels in three-phase electrical systems with nominal voltages above 1 kV. Serving as an application guide to IEC 60071-1, it provides authoritative guidance for determining rated withstand voltages, justifying their association with standardized equipment voltage ratings, and ensuring insulation coordination for equipment reliability and safety. This standard holds the status of a horizontal standard as defined by IEC Guide 108 and is relevant across a broad spectrum of power systems and high-voltage applications worldwide.

Key Topics

IEC 60071-2:1996 addresses critical concepts and procedures essential to insulation coordination:

• Selection of Insulation Levels: Guidance on determining rated withstand voltages for equipment ranges defined in IEC 60071-1.
• Voltage Stress Types: Addresses phase-to-phase, phase-to-earth, and longitudinal insulation voltages, considering all sources of voltage stress-continuous, temporary, slow-front, and fast-front overvoltages, as well as combined stresses.
• Protective Devices: Explains the characteristics and application of standardized overvoltage protective devices, such as non-linear resistor-type surge arresters with series gaps, metal-oxide surge arresters, and spark gaps.
• Insulation Co-ordination Procedures: Details processes for assessing insulation requirements based on system studies, statistical risk evaluation, and testing protocols.
• Standard Voltages and Testing: Describes the relationship between service voltage stresses and standard withstand voltages, including typical test procedures and atmospheric correction factors.
• Special Considerations: Offers practical insights for insulation co-ordination of overhead lines and substations, addressing unique stresses and environmental factors.

Applications

IEC 60071-2:1996 is crucial for professionals engaged in:

• High Voltage Equipment Design and Specification: Manufacturers and engineers use this standard to specify appropriate insulation levels, ensuring equipment withstands operational and overvoltage stresses during its lifecycle.
• Utility and Transmission Operators: Power utilities rely on the guideline to coordinate insulation across interconnected substations, overhead lines, and network components, thereby minimizing failure risk and improving operational reliability.
• System Studies and Risk Assessment: Electrical engineers use these procedures to analyze possible voltage stresses and select suitable insulation profiles using statistical and deterministic methods.
• Testing and Compliance: Test laboratories and quality assurance specialists refer to the prescribed withstand voltages and test conversion factors to verify compliance with international performance benchmarks.
• Power System Upgrades and Expansions: When introducing new equipment or extending high-voltage lines, this standard helps align insulation specifications with prevailing voltage classes and protective device capabilities.

Related Standards

For comprehensive insulation co-ordination, IEC 60071-2:1996 should be used alongside several related standards:

• IEC 60071-1: Insulation co-ordination – Part 1: Definitions, principles, and rules
• IEC 99-1, IEC 99-4, IEC 99-5: Surge arresters – Characteristics, testing, and application
• IEC 60-1: High-voltage test techniques – General definitions and requirements
• IEC 56: High-voltage alternating-current circuit-breakers
• IEC 505: Insulation system evaluation guidance
• IEC 507: Artificial pollution testing on high-voltage insulators
• IEC 721-2-3: Classification of environmental conditions
• IEC 815: Guide for selection of insulators for polluted conditions

Conclusion

Adhering to IEC 60071-2:1996 ensures optimal insulation coordination in high-voltage networks, maximizing system reliability and service continuity. Its wide applicability across electrical engineering, equipment manufacturing, utility operations, and testing makes it an essential resource for those focused on high-voltage system safety and performance. For more detailed information or updates, refer to the official IEC website or the latest editions of related standards.