Overview
IEC 60660:1999 is an international standard published by the International Electrotechnical Commission (IEC) that defines the testing requirements for indoor post insulators made of organic material. This standard applies to electrical systems with nominal voltages greater than 1,000 V and up to, but not including, 300 kV. It is specifically designed for insulators used in air at atmospheric pressure and operating on alternating current with frequencies not exceeding 100 Hz. Importantly, composite insulators are excluded from this standard.
This edition-second and revised since 1979-addresses the performance, durability, and safety testing of indoor post insulators, ensuring their reliable operation in medium- and high-voltage electrical installations or equipment.
Key Topics
The IEC 60660 standard covers a comprehensive range of test procedures to evaluate the suitability and robustness of organic post insulators for indoor use:
- Scope and Definitions: Clarifies the applicable voltage range, types of insulators covered, service conditions, and technical terminology.
- General Testing Requirements: Classifies the types of tests (type, sample, routine) and outlines quality assurance protocols.
- Electrical Tests:
- Lightning impulse voltage withstand tests (dry conditions)
- Power-frequency voltage withstand tests (dry conditions)
- Partial discharge extinction voltage measurement
- Lightning impulse puncture tests evaluating dielectric strength
- Mechanical Tests:
- Mechanical failing load and bending strength under various temperatures
- Deflection measurements under load at normal temperature
- Environmental and Material Tests:
- Water absorption evaluation
- Ageing and humidity resistance testing inside controlled atmospheres
- Flammability assessment for fire safety
- Resistance to rapid temperature variations
- Dimensional and Visual Inspection: Verification of form and position tolerances, and routine visual examinations.
- Documentation Requirements: Detailed record-keeping for test results and procedures.
This structured testing regimen ensures that indoor post insulators made of organic material meet strict international quality, safety, and performance standards.
Applications
IEC 60660:1999 is essential for manufacturers, testing laboratories, utilities, and engineers involved in the design, procurement, testing, and maintenance of electrical installations employing indoor post insulators within the specified voltage range. Typical applications include:
- Indoor high-voltage switchgear and apparatus requiring reliable insulation
- Electrical substations and control rooms with indoor installations
- Power transformers and related electrical equipment supporting medium- and high-voltage distribution
- Quality assurance and compliance testing during production and on-site acceptance
- Development of new organic insulating materials and post insulator designs for indoor use
By adhering to these standard tests, stakeholders ensure that post insulators possess adequate electrical strength, mechanical integrity, environmental reliability, and safety under operational stresses, contributing to the stable and safe operation of electrical power systems.
Related Standards
To fully understand and implement IEC 60660:1999, it is recommended to consult complementary IEC standards and documents, including:
- IEC 60071-1: Insulation co-ordination - Part 1: Definitions, principles, and rules, which defines voltage ranges and insulation requirements referenced by IEC 60660.
- IEC 60050 (International Electrotechnical Vocabulary): For precise definitions of electrical terminology used throughout the standard.
- IEC 60027, IEC 60417, IEC 60617: Standards relating to graphical symbols, letter symbols, and graphical symbols for use in electrical technology, important for documentation and diagrams.
- Other IEC standards on composite insulators and outdoor insulator testing, as IEC 60660 explicitly excludes composite types and outdoor applications.
Together, these standards form a harmonized framework supporting the design, testing, and certification of electrical insulators and contributes to global standardization and interoperability in the electrical power industry.
Keywords: IEC 60660, indoor post insulators, organic material insulators, high voltage insulator testing, lightning impulse test, power frequency test, mechanical load test, electrical insulation standards, medium and high voltage insulators, IEC electrical standards, insulation coordination, electrical safety testing.