In recent years, many hydro power plants were modified to pump storage operation. This changes the loading conditions and new monitoring concepts are required. We developed a fiber Bragg grating based monitoring system which was installed inside a hydro power dam in 2013. This paper reports on detailed investigations of this network using an optical backscatter reflectometer, which allows distributed strain sensing with a very high spatial resolution up to millimeters. Therefore, an analysis of the strain profile between two anchoring points of a FBG sensor can be performed. In addition to distributed sensing, the different wavelengths of the FBGs are determined in the frequency domain to verify the results of a classical FBG interrogator. These comparisons and further laboratory studies prove the suitability of the fiber optic system and demonstrate that a detailed analysis of FBG networks using optical backscatter reflectometry can provide valuable insights.

Date Published: 27 April 2017
PDF: 12 pages
Proc. SPIE 10208, Fiber Optic Sensors and Applications XIV, 102080R (27 April 2017); doi: 10.1117/12.2262410

Published in SPIE Proceedings Vol. 10208:
Fiber Optic Sensors and Applications XIV
Christopher S. Baldwin; Gary Pickrell; Henry H. Du, Editor(s)