Effect of Lightning Strikes on Optical Fibres Installed on Overhead Line Conductors

This paper presents a new experimental investigation to study the effect of lightning strikes on optical fibres installed in overhead line shield/ground wires. High current laboratory experiments were set up at Cardiff University's Morgan-Botti Lightning Laboratory, where the A, B, C, D waveforms, as recommended by current aerospace standards, can be generated. The test source consists of capacitive current generators able to deliver up 220 kA into short circuit. Two types of optical ground wire (OPGW) test conductors were used: OPGW-DABB 48E9 (AA/ACS 100/33) and OPGW-DABB 48E9 (AA/ACS 148/35). Various lengths of the test conductors were used in the experimental investigation (6 to 18 m). The rate of change of state of polarisation (SOP) of light in the fibre was measured using a specialist polariser meter system when lightning impulse currents of varying magnitudes were applied to the OPGW conductors. Preliminary test results show significant effects.