Rationales and Expectations with Upcoming New Line Surge Arrester (LSA) Standard IEC/IEEE 60099-11

Line Surge Arresters (LSAs) play a critical role in enhancing the reliability of overhead power lines by mitigating lightning-induced faults. Despite their widespread adoption worldwide, the standardization of LSAs remains inconsistent, particularly for Non-Gapped Line Arresters (NGLAs), which currently lack a dedicated testing framework tailored to their unique mechanical and electrical stress conditions. The upcoming IEC/IEEE 60099-11 standard aims to address these long-standing gaps by introducing a unified classification system, enhanced testing protocols, and improved performance requirements for both Externally Gapped Line Arresters (EGLAs) and NGLAs. This paper presents the rationale and key expectations for the new LSA standard, highlighting challenges associated with current LSA applications, including failure rates, inadequate mechanical testing, and inconsistencies in existing IEC and IEEE standards. A critical advancement in IEC/IEEE 60099-11 is the adoption of a $2 / 20 \mu$ s waveshape for LSA classification, aligning with field experience and system studies on lightning performance. Additionally, the standard will establish new mechanical test requirements, including vibration, bending moment, and torsional withstand tests, to ensure the long-term reliability of LSAs under harsh operational conditions. By harmonizing IEC and IEEE requirements, IEC/IEEE 60099-11 will provide a comprehensive and standardized framework for evaluating and deploying LSAs, improving reliability and operational efficiency for power utilities worldwide. The paper underscores the importance of collaborative efforts among standardization bodies, manufacturers, and utilities in successfully implementing the new standard and advancing surge protection technology for overhead transmission and distribution networks.