Overview
IEC TS 62371:2008, published by the International Electrotechnical Commission (IEC), defines the characteristics of hollow pressurised and unpressurised ceramic and glass insulators used in electrical equipment operating at rated voltages greater than 1000 V. This specification focuses on insulators intended for general use, including those designed for permanent gas pressure in switchgear and controlgear. By standardizing dimensional and mechanical characteristics, IEC TS 62371 ensures interchangeability among products of the same type, supporting unified practices in high-voltage applications.
Hollow insulators addressed by this standard are primarily used as components within larger electrical equipment, rather than being directly applied to power systems. Typical applications include circuit-breakers, instrument transformers, surge arresters, and bushings, among others. This technical specification applies to insulators deployed in clean or lightly polluted environments where seismic qualification is not required.
Key Topics
IEC TS 62371:2008 covers the following key aspects:
- Scope of Application: Applies to both ceramic and glass hollow insulators (pressurised and unpressurised) used indoors and outdoors in high-voltage electrical equipment above 1000 V AC (up to 100 Hz) or above 1500 V DC.
- Dimensional and Mechanical Characteristics: Specifies essential properties such as:
- Height
- Arcing distance
- Creepage distance
- Diameters of insulating parts and inner hollow
- Withstand bending moment and inner pressure load (as required)
- Fixing structures (with or without metal fittings)
- Types Covered:
- Straight or taper type, both with and without metal fittings
- Interchangeability: Enables easier replacement and procurement by ensuring compatibility among insulators of the same specification.
- Reference to Electrical Characteristics: While electrical performance is dependent on the host equipment, standard lightning impulse withstand voltage (as in IEC 60071-1) is referenced for classification purposes.
- Marking and Designation: Insulators are identified using a code that incorporates parameters such as material, type, height, diameter, fixing arrangement, and shed profile.
Applications
IEC TS 62371-compliant hollow ceramic and glass insulators play a pivotal role in the safe and reliable operation of high-voltage electrical equipment. Common applications include:
- Switchgear and Controlgear: Insulators with permanent gas pressure for insulation and containment.
- Circuit-Breakers and Disconnectors: Used as critical dielectric barriers and structural supports.
- Instrument Transformers: Provide insulation and mechanical robustness for measurement and monitoring devices.
- Surge Arresters and Capacitors: Protect equipment from transient overvoltages and ensure reliable operation.
- Bushings and Cable Sealing Ends: Support the passage of conductors through grounded barriers with effective insulation.
Standardization of insulator types, mounting arrangements, and mechanical strength supports cost savings, efficient inventory management, shortens delivery times, and enhances maintainability.
Related Standards
Referencing and harmonization with other IEC standards ensures comprehensive coverage and alignment across high-voltage insulation equipment:
- IEC 62155: Hollow pressurised and unpressurised ceramic and glass insulators for use in electrical equipment with rated voltages greater than 1000 V – test methods and acceptance criteria.
- IEC 60071-1: Insulation co-ordination – definitions, principles, and rules.
- IEC 60815-1 & IEC 60815-2: Selection and dimensioning of high-voltage insulators for polluted conditions.
- IEV 60050(471): International Electrotechnical Vocabulary – Insulators.
Summary
IEC TS 62371:2008 provides essential guidance on the dimensional and mechanical characteristics of hollow ceramic and glass insulators, ensuring compatibility and interchangeability for high-voltage electrical equipment. The standard advances uniformity and efficiency in electrical equipment design, manufacturing, and maintenance, supporting safe, reliable, and cost-effective operation in the power industry.