HD 578 S1:1992

Overview

HD 578 S1:1992 (CLC) specifies the characteristics of indoor and outdoor post insulators for electrical systems with nominal voltages greater than 1 kV and frequency not greater than 100 Hz. The standard applies to post insulators and post insulator units made of ceramic or glass for indoor and outdoor service, and to post insulators of organic material intended for indoor service. It can also be regarded as a provisional reference for insulators used on direct current (DC) systems. HD 578 S1:1992 is aligned with IEC 273:1990 and is indexed under ICS 29.080.10 (Insulators).

Key topics and requirements

The standard covers essential aspects needed to select, manufacture and verify post insulators for medium- and high-voltage applications, including:

• Scope and definitions for post insulators and post insulator units used in AC systems >1 kV (≤100 Hz)
• Material classes: ceramic, glass (indoor/outdoor) and organic materials (indoor)
• Performance characteristics: electrical and mechanical behavior appropriate to their intended service
• Environmental considerations: suitability for indoor vs outdoor exposure and related durability factors
• Testing and quality criteria: requirements for type and routine verification to ensure compliance (electrical and mechanical testing, inspection and marking)
• Classification and marking to aid specification, procurement and installation (Note: this summary describes topic areas; the standard document contains the detailed test procedures, acceptance criteria and dimensional/marking rules.)

Practical applications

HD 578 S1:1992 is used to ensure reliability, safety and interchangeability of post insulators in:

• Substations and switchgear assemblies operating above 1 kV
• Indoor insulating supports in electrical equipment and distribution panels
• Outdoor support insulators subject to weather and contamination (ceramic/glass types)
• Design and specification of insulation systems where long-term electrical and mechanical performance is required

Who uses this standard

• Insulator manufacturers and material suppliers (ceramic, glass, organic)
• Power utilities and grid owners specifying insulator performance
• Electrical design engineers and specifiers writing procurement documents
• Test laboratories performing conformity and type tests
• Contractors and maintenance teams verifying correct replacement parts

Related standards

• IEC 273:1990 (corresponding international reference cited by HD 578 S1:1992)
• Other CLC/CENELEC and IEC standards on insulators and high-voltage testing (consult national catalogues for cross-references)

Keywords: post insulators, indoor and outdoor post insulators, >1 kV, ceramic insulators, glass insulators, organic insulators, HD 578 S1:1992, CLC, IEC 273, insulator characteristics, electrical insulation standards.