IEC 60099-8:20 17作为IEC 60099-8:20 17 RLV提供，其中包含国际标准及其红线版本，显示了与上一版本相比技术内容的所有变化。 IEC 60099-8:20 17涵盖了应用于架空输电和配电线路的具有外部串联间隙的金属氧化物避雷器（外部间隙线路避雷器（EGLA）），仅用于保护绝缘子组件免受雷电引起的闪络。？本文件定义的电涌放电器仅用于保护绝缘子组件免受雷电引起的过电压。因此，由于金属氧化物电阻器不会永久连接到线路上，因此本文档不考虑以下项目: -开关脉冲火花过电压； -陡峭电流和开关电流脉冲下的残余电压；-热稳定性； -长持续时间电流脉冲耐受负载； -避雷器的工频电压对时间特性； -隔离开关测试； -通过工频电压老化负载。 考虑到架空输配电线路的特殊设计理念和特殊应用，介绍了一些独特的要求和试验，如绝缘子耐受性与EGLA保护等级协调的验证试验、跟随电流开断试验、机械负荷试验等。本文件不包括EGLA外部串联间隙与绝缘子并联安装的设计。第二版取消并取代了2011年出版的第一版。本版构成技术修订版。与上一版相比，此版本包括以下重大技术变更:雷电放电能力测试已完全重写并重新命名为测试，以验证重复电荷转移额定值，雷电放电Qrs，以反映IEC 60099-4 Ed.3（2014）中引入的关于金属氧化物避雷器能量和电荷处理能力额定值新方法的变化。除了评估MO电阻器性能的测试之外，还介绍了评估EGLA串联间隙性能的程序。 -包括了本标准第1版的遗漏，特别是RIV测试和用于确定EGLA SUV部分的热时间常数的方法。 -增加了新术语的定义 -第1版中的若干注释已转换为规范性要求 关键词:外部间隙线路避雷器（EGLA），雷电引起的过电压

IEC 60099-8:2017 is available as IEC 60099-8:2017 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60099-8:2017 covers metal-oxide surge arresters with external series gap (externally gapped line arresters (EGLA)) that are applied on overhead transmission and distribution lines, only to protect insulator assemblies from lightning-caused flashovers.？ This document defines surge arresters to protect the insulator assembly from lightning-caused over-voltages only. Therefore, and since metal-oxide resistors are not permanently connected to the line, the following items are not considered for this document:
- switching impulse spark-over voltage;
- residual voltage at steep current and switching current impulse;
- thermal stability;
- long-duration current impulse withstand duty;
- power-frequency voltage versus time characteristics of an arrester;
- disconnector test;
- aging duties by power-frequency voltage.
Considering the particular design concept and the special application on overhead transmission and distribution lines, some unique requirements and tests are introduced, such as the verification test for coordination between insulator withstand and EGLA protective level, the follow current interrupting test, mechanical load tests, etc. Designs with the EGLA's external series gap installed in parallel to an insulator are not covered by this document. This second edition cancels and replaces the first edition published in 2011. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
The Lightning discharge capability test has been completely re-written and re-named to Test to verify the repetitive charge transfer rating, Qrs with lightning discharges to reflect changes introduced in IEC 60099-4 Ed.3 (2014) regarding new methods for rating the energy and charge handling capability of metal-oxide arresters. In addition to testing to evaluate the performance of the MO resistors, procedures for evaluating the performance of the EGLA series gaps have been introduced.
- Omissions from Ed. 1 of this standard have been included, notably an RIV test and a means for determining the thermal time constant of the SUV portion of the EGLA.
- Definitions for new terms have been added
- A number of NOTES in Ed. 1 have been converted to normative requirements
Keywords: externally gapped line arresters (EGLA), lightning-caused over-voltages