In the ever-evolving landscape of high-voltage technology, Externally Gapped Line Arresters (EGLA) are emerging as a transformative solution, and the French TSO, Réseau de Transport d'Électricité (RTE), is at the forefront of unraveling their potential. Originating in Japan 40 years ago, EGLA combines Metal Oxide Varistors (MOVs) with air gaps to prevent lightning-induced outages on overhead lines. Despite significant global development, the full benefits of EGLA remain underappreciated, prompting RTE to share valuable insights on their applications.

RTE's involvement sheds light on EGLA's role in addressing power grid challenges, particularly in safety and lightning protection. Authors Luis Diaz, an R&D Engineer at the National Center of Expertise for the French Transmission System Operator (TSO), RTE and Florent Giraudet a consultant for lightning performance and surge arrester technologies aim to demystify EGLA technology in their article, providing comprehensive insights into its technical intricacies, safety protocols, and operational efficiencies. Their article targets a diverse readership, from industry experts to policymakers, educating them on EGLA's untapped potential for enhancing grid reliability and safety.

The journey of EGLA adoption in France began in the late 1990s when former TSO EDF incorporated EGLA to address the challenge of 50Hz fault currents following lightning flashovers. The unique setup in France, with RTE as the sole TSO, streamlined EGLA standardization across the country. Challenges arose, including insulation coordination and safety concerns, but innovative approaches were adopted, contributing to EGLA's success.

RTE's experience showcases EGLA's effectiveness in reducing outage rates and mitigating ground potential rise risks. Case studies reveal a 60% reduction in yearly outage rates for a 225kV line near Paris and the use of EGLAs in a residential area in the South of France. The implementation of EGLA aligns with France's energy policies, emphasizing environmental protection and safety.

Looking ahead, RTE plans to incorporate advanced fault indicator technology in future EGLA installations and assess the demand for a 400kV EGLA solution. Strategically, RTE aims to quantify risk reduction, promoting EGLAs as a cost-effective solution. Despite challenges in live line installations and maintenance, EGLAs remain a beacon of innovation in power systems.

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