Introduction
The International Electrotechnical Commission (IEC) has unveiled its latest standard, IEC Technical Specification TS 62818-1: Conductors for Overhead Lines – Fiber Reinforced Composite Core Used as Supporting Member Material – Part 1: Polymeric Matrix Composite Cores. This specification establishes standardized testing methods for fiber reinforced composite (FRC) cores, which are increasingly utilized in overhead line conductors. Known for their exceptional strength-to-weight ratio and resistance to environmental conditions, FRC cores are becoming an essential material in modern electrical infrastructure.
Key Differences Between IEC TS 62818-1 and ASTM B987
While IEC TS 62818-1 and ASTM B987 are both pivotal in the evaluation of fiber reinforced composite cores, there are notable distinctions in their requirements:
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Test Requirements Both standards feature similar type test protocols, which simplifies the process for manufacturers looking to comply with both. However, IEC 62818-1 does not set specific minimum acceptance criteria for properties like tensile strength and elastic modulus, whereas ASTM B987 stipulates minimum values for these critical characteristics.
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Strength Grades and Classes Unlike ASTM B987, which categorizes composite cores into defined strength grades or classes, IEC 62818-1 leaves the categorization of cores up to agreement between the purchaser and the manufacturer. This flexibility allows for customization based on project-specific needs.
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Galvanic Layer Thickness ASTM B987 includes explicit minimum thickness requirements for the galvanic layer of the core, while IEC 62818-1 merely acknowledges the presence of the galvanic layer. The specification does not impose a minimum thickness but focuses on its inclusion in the final conductor design, whether metallic or non-metallic.
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Aging Tests A significant contrast lies in the aging test methodologies. ASTM B987 uses a 52-week heat exposure test to assess long-term durability, while IEC 62818-1 employs an accelerated aging approach using the Arrhenius method. This approach involves subjecting the material to various elevated temperatures, and the results are extrapolated to predict the material’s performance over 30 to 50+ years. This predictive method offers an advanced means of estimating the material’s longevity under realistic conditions.
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Testing Flexibility IEC 62818-1 provides greater testing flexibility by leaving the acceptance criteria to be negotiated between the manufacturer and purchaser. This contrasts with ASTM B987, which sets fixed minimum values for important properties like tensile strength and modulus, offering less room for adjustments in material specifications.
CTC Global’s Contribution to Advancing These Standards
CTC Global, a pioneer in high-performance conductor solutions, plays a crucial role in supporting the testing and qualification of fiber reinforced composite cores. The company’s ISO/IEC 17025-accredited laboratory in Irvine, California, is equipped to conduct a broad range of tests required by both IEC 62818-1 and ASTM B987. This accreditation highlights CTC Global’s commitment to excellence in testing and its ability to provide reliable, data-driven insights on the performance of High Temperature Low Sag (HTLS) conductor materials.
In particular, CTC Global has completed extensive Arrhenius testing of composite cores, providing invaluable data for the verification of long-term material performance. Their testing capabilities align perfectly with the requirements of IEC 62818-1, particularly regarding accelerated aging tests, which are vital in confirming the durability of these advanced materials.
Conclusion
The publication of IEC TS 62818-1 marks a significant advancement in the standardization of fiber reinforced composite core testing for overhead line conductors. While the specification differs from ASTM B987 in certain aspects, both standards share common testing protocols, providing manufacturers with a unified approach to ensuring product quality. CTC Global’s state-of-the-art testing facilities and expertise in composite materials position the company as a key partner in this evolving sector, ensuring that the next generation of overhead line conductors meets the highest standards of performance, safety, and reliability.
