In this work, a low-cost multipoint fiber optic sensor system for real-time monitoring of the temperature distribution on transformer cores was demonstrated. The temperature sensors are based on multi-mode random air hole fibers infiltrated with CdSe/ZnS quantum dots. Quantum dots resided in multi-mode random-hole core regions can be optically excited by guided UV light with extremely high quantum efficiency. The photoluminescence intensity dependence on the ambient temperatures were used to gauge the local operational temperature of transformer under strong magnetic fields. Multiplepoint temperature sensing systems were developed by bundling quantum dots infiltrated random air hole fibers together. Using a low-cost UV diode laser as a light source and a CCD camera as detector, hundreds of fiber sensors can be interrogated at low cost. This multi-point fiber sensor system, which is free from electromagnetic interference, was used to monitor temperature fluctuation of transformer from the room temperature up to 96°C with better than 1°C accuracy. The proposed fiber optic sensing scheme could overcome the shortcomings of traditional electric sensors and provide a versatile and low-cost approach to map the temperature distribution of electric power systems such as transformers operated in strong electromagnetic fields.
Real-time temperature mapping is important to offer an optimized thermal design of efficient power transformers by solving local overheating problems. In addition, internal temperature monitoring of power transformers in operation can be leveraged for asset monitoring applications targeted at fault detection to enable condition based maintenance programs. However transformers present a variety of challenging environments such as high levels of electromagnetic interference and limited space for conventional sensing systems to operate. Immersion of some power transformers within insulation oils for thermal management during operation and the presence of relatively large and time varying electrical and magnetic fields in some cases also make sensing and measurement technologies that require electrical wires or active power at the sensing location highly undesirable. In this work, we investigate the dynamic thermal response of standard single-mode optical fiber instrumented on a compact transformer core by using an optical frequency-domain reflectometry scheme, and the spatially resolved on-line monitoring of transformer core temperature rise has been successfully demonstrated. It is found that spectral shifts of the fiber-optic sensor induced by the temperature rises are strongly related to the locations inside the transformer as would be expected. Correlation between thermal behavior of the transformer core as derived from standard IR-based thermal imaging cameras and fiber-optic sensing results is also discussed. The proposed method can easily be extended to cover situations in which high accuracy and high spatial resolution thermal surveillance are required, and offers the potential for unprecedented optimization of magnetic core designs for power transformer applications as well as a novel approach to power transformer asset monitoring.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.