1997 Volume 117 Issue 3 Pages 256-261
In the first section of this paper, the author reports the measurment of a tensile strain distribution on field-installed OPGW (optical fiber composited over-head ground wire) using the method of Brillouin optical fiber time domain analysis (BOTDA). The strain differences between strung sections and non-strung sections of OPGW are clealy differenciated and observed. The obtained differences are about 0.1% in the winter and about 0.2% in the summer. Those values are less than the allowable strain on the OPGW. An analysis of a relationship between measured strain and temperature is also described. It is found that the temperature dependency of strain data agrees quite well with a thermal expansion coefficient of OPGW.
In the second section, it is introduced a new strain measurement technique named “Ring Amplification Method”, which enables measurements of rapidly varying strains such as the one caused by galloping. A principle and a measurable distance by this method are studied, and it is clarified that this method is applicable to a measurement on a long-extended fiber up to 40km. Furthermore, the ability of measuring the time-varying strain and its distribution has been demonstrated in the basic experiments.
The transactions of the Institute of Electrical Engineers of Japan.C
The Journal of the Institute of Electrical Engineers of Japan