EGLA line surge arresters have an external spark gap placed in series that galvanically isolates the active part of the arrester from the line voltage in normal conditions. In case of lightning, the spark gap is ignited and the overvoltage is safely discharged to the ground. EGLA line surge arresters prevent all insulator flashovers caused by lightning strikes. As such, EGLA increases network stability as well as the availability of the overhead line.
An additional benefit of EGLA line surge arresters is that there is no leakage current, because the series gap disconnects the active part of the EGLA from the system voltage.
This compact design is often the only option to install line surge protectors on existing towers with very small clearances.
Siemens EGLA line surge arresters are available for system voltages of up to 550 kV.
All Siemens EGLAs are designed and tested to comply with the latest IEC 60099-8 standard, which became effective in January 2011.