Externally gapped line arrester a comprehensive review

The externally gapped line arrester (EGLA) is a type of arrester that optimizes the positive characteristics of the oldest arrester design component, a series gap, and the newest arrester design component, a metal oxide varistor (MOV). Combining these two components yields a significant improvement in line protection and reliability options for utilities. However due to negative characteristics of gapped technology when used in series with an earlier varistor type silicon carbide (SiC) arresters, the EGLA is experiencing substantial acceptance issues. The purpose of this document is to clarify the difference between these two technologies and to outline the fundamental characteristics that make this arrester design the optimal for line protection.