Here's the answer

April 27, 2020   photos  

First of all, As much as being an indication of electrical lines to aircraft, it functions as vibration dampers. Vibrations are a cause of conductor breaking, though over relatively long periods of time. It prevents the conductors from reaching resonant vibrations. In addition to this, it is used to make sure that all pilots of little air navigation specially at low altitudes can see the high voltage wires. Its is used for indication of high voltage line .and also for mainly giving the tension of cable.