Grounding of optical fiber control cable in substation under lightning stroke

Abstract

The optical fiber control cable in a substation would be destroyed due to the incorrect grounding method, when a lightning strike hits the substation. The method to generate interference on an optical fiber cable by lightning stroke was analyzed. Different grounding methods were comprehensively discussed by a numerical calculation method. The ideal grounding method for optical fiber cable is to ground the internal strengthening core and the outer metal sheath in the meantime. The electrical field intensity applied inside the optical fiber cable increases with the soil resistivity. The frequency of the interference source is an important factor to affect the interference electrical field generated inside the optical fiber cable. The metal strengthening core has a high potential when an interference source is applied, so the stroke from it to the interior of the terminal equipment should be avoided.