Study on Brillouin Scattering Based OPGW Equivalent Icing Thickness Conversion

Weighing method and video monitoring method are currently adopted to monitor icing condition on transmission lines. However, monitoring range of these methods is limited, and these methods need to install active sensing devices and wireless communication devices which may fail to work due to some factors such as atrocious weather, inadequate power supply. Nowadays, distributed optical fiber sensing technology is widely used in temperature and strain monitoring of oil pipe and tunnels because of its advantage in long monitoring distance and capacity in anti-electromagnetic interference. This paper applies distributed optical fiber sensing technology in the icing condition monitoring of transmission lines for the first time. Because temperature and strain information can be obtained simultaneously through Brillouin frequency shift, the Brillouin scattering based optical fiber sensing technology can be used to identify the condition and thickness of ice on optical fiber composite overhead ground wire (OPGW) which can finally conduct the anti-icing work. But how to transmit the OPGW strain information into ice thickness is a problem to face. This paper deduces the calculation formula of ice thickness based on the relationship between Brillouin frequency shift and temperature & strain. Then a fiber Brillouin scattering based OPGW icing identification system is designed on basis of the results. Several experiments are carried out to verify the formula and the designed system is successfully applied to the Zhaotong power system. And the results verify the deduced formula and show low error between theoretical icing thickness and the tested results.