Study of OPGW performance against lightning strikes for 1000 kv AC transmission line in China

This paper investigates the ability to withstand lightning strikes by OPGW cables used in the ultra high-voltage (UHV) power transmission lines. With the same annual average thunderstorm days, the amount of the electric charge transferred at 1000 kV is almost an order of magnitude higher than that at 500 kV. It has been found that the best way to improve OPGW performance against lightning strikes is to use an all aluminum-clad steel wire stranded structure, and to increase the diameter of the outer layer wires as much as possible. Three types of OPGW cables with different structures have been designed and fabricated for UHV transmission lines. The lightning strike tests with both 200 and 250 Coulombs (C) charge transfers are carried out on three types of samples. After all tests, there are almost no attenuation increases for the single-mode fiber at 1550nm wavelength. The lighting strikes to the OPGW have no visible influence on the optical performance. No wires were found to be broken after five 200C lightning shots for two types of OPGW cable. One of these two types of OPGW cables has been operated in the 1000 kV power lines successfully.