Ice coating severely impairs the safe operation of optical fiber composite overhead ground wire (OPGW). The Brillouin optical time domain reflectometer (BOTDR) utilizes communication fibers within OPGW as both status sensing and information transmission media

which may offer an ice monitoring solution. However

existing temperature-strain demodulation methods of BOTDR cannot be directly applied to OPGW ice monitoring due to the cross-sensitivity of optical fibers to temperature and strain. This paper proposes a method for monitoring the equivalent ice thickness of OPGW in an isolated tension section by utilizing the temperature measured by micro‑meteorological terminals on overhead transmission lines to demodulate the tension from BOTDR. When the error between BOTDR-measured temperature t1 and micro-meteorological terminal temperature tm falls within their accuracy range

only ice-induced temperature sensing is required without demodulation; when the temperature error exceeds the accuracy range

indicating that BOTDR Brillouin frequency shift νB is simultaneously affected by OPGW temperature and tension

the micro-meteorological terminal temperature is employed to demodulate BOTDR tension

and the inclined parabolic equation of isolated tension section is combined to calculate equivalent ice thickness of OPGW. Ice coating experiments based on this method were conducted at the Guizhou Meihua Mountain Field Scientific Observation Station for Freezing Disaster and Equipment Safety. Comparative studies with the weighing method and manual ice observation show that

for the equivalent ice thickness of isolated tension section OPGW

the maximum deviation between BOTDR monitoring values and the weighing method is 0.60 mm

with a maximum relative error of 5.38%

and the maximum relative error compared with manual observation is 8.95%. These results validate the accuracy of the proposed methodology.