Maintenance of the OPGW using a distributed optical fiber sensor

Optical fiber ground wire (OPGW) is used as the earth line to protect the electric power instruments and it is also an information transmission line for electric power system communication. It is important to find an effective way to monitor the status of the OPGW, so as to avoid some possible dangers that may lead power failure or provide quick power recovery after the fault happens. Distributed optical fiber sensors should be the best way for OPGW maintenance, for it can monitor the health of the optical fiber transmission lineand sense the temperature and/or strain along the OPGW. Fiber break, lightning stroke and ice covering are potential dangers that need to be paid close attention to, and they are the main factors that cause OPGW failure. To monitor these dangers, Brillouin optical time domain reflectometry (BOTDR) is employed. The temperature sensing characteristics of BOTDR makes it become a tool for lighting stroke location, and the ability for strain monitoring benefits the ice covering status analysis. Experimental results demonstrate that the BOTDR can sensitively locate the lightning stroke incidents with the quantity of electric discharging larger than 100C and in the ice covering condition the strain feature appears only when the extra tensile force on the OPGW is over 30kN. Therefore, the BOTDR can well play its roles.