Wind turbine blades are made of composite materials and reach a length of more than 42 meters. Developments
for modern offshore turbines are working on about 60 meters long blades. Hence, with the increasing height
of the turbines and the remote locations of the structures, health monitoring systems are becoming more and
more important. Therefore, fiber-optic sensor systems are well-suited, as they are lightweight, immune against
electromagnetic interference (EMI), and as they can be multiplexed. Based on two separately existing concepts
for strain measurements and lightning detection on wind turbines, a fused system is presented. The strain
measurement system is based on a reflective fiber-Bragg-grating (FBG) network embedded in the composite
structure of the blade. For lightning detection, transmissive &fiber-optic magnetic field sensors based on the
Faraday effect are used to register the lightning parameters and estimate the impact point. Hence, an existing
lightning detection system will be augmented, due to the fusion, by the capability to measure strain, temperature
and vibration. Load, strain, temperature and impact detection information can be incorporated into the turbine's
monitoring or SCADA system and remote controlled by operators. Data analysis techniques allow dynamic
maintenance scheduling to become a reality, what is of special interest for the cost-effective maintenance of large
offshore or badly attainable onshore wind parks. To prove the feasibility of this sensor fusion on one optical
fiber, interferences between both sensor systems are investigated and evaluated.
Power cables should be operated at an adequate temperature level. Therefore, numerous power utilities have installed
optical distributed temperature sensing (DTS) systems to measure the temperature of underground cables. Protection and
metering systems used in power systems require measurements of the current flowing in the high-power conductors as
well. Optical current sensors achieve increasing attention and acceptance for this application due to their inherent
electrical insulation, high bandwidth, and immunity to EMI. DTS systems are based on spontaneous Raman scattering or
Brillouin scattering, which use spectral information in the reflected light, whereas optical current sensors are based on
the Faraday effect, which changes the intensity of transmitted light. This paper proposes a novel design of a combined
optical temperature and current measurement system, using both physical effects. A first measurement setup is described,
and first results are discussed. Thereby, the specifications for the combined data acquisition and data processing unit are
analyzed in order to optimize the accuracy and the reliability of each subsystem and the whole system.
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