Virginia Tech Photonics Center to Develop Sensors for Power Systems
BLACKSBURG, Va., Aug. 30, 2011 — Looking for novel sensing technologies that will aid in everything from clean energy technology to the monitoring of various gases, the US Department of Energy (DoE) and the Electric Power Research Institute (EPRI) have selected Virginia Tech’s Center for Photonics Technology to lead efforts in three projects. The awards are valued at a total of more than $3.2 million.
The photonics center has a history of achievements in the area of optical fiber sensors. Anbo Wang, Virginia Tech professor of electrical and computer engineering and director of the center, holds a number of patents on sensing technologies.
One of his latest DoE awards is critical to the development of clean energy technology in America, according to the government agency.
This new award requires the center to work on the creation of a high-temperature distributed sensing platform and on improvements to the operations of fossil energy power plants. The center is one of three selected by the DoE to develop these technologies aimed at ensuring the efficient operation of advanced zero-emission power systems and the improvement of operations at existing fossil energy power plants.
The DoE is asking Virginia Tech to develop a technology for remote fiber optic generation and for the detection of acoustic waves for structural health monitoring. The envisioned technology would require no electric power supply at the monitoring site and at the detected acoustic signature, as well as the additional returned optical signal. It would allow the recording of information about multiple material conditions, including temperature, strain, corrosion and cracking.
The project will last 36 months, and DOE funding will total $1.2 million.
In the second DoE project, Wang and his colleagues will develop a sensing platform to monitor the varying space and time properties of a gasifier’s refractory wall.
In a gasifier, a carbon-based material such as coal or petroleum can be converted at a high temperature into a gas, including hydrogen, carbon monoxide or a synthetic. The temperatures may exceed 1000 °C. The term refractory refers to the materials used to line the walls of the gasifiers, protecting the shell of the gasification chamber from the very intense process.
Wang’s sensors will be used to identify problem areas such as localized hot spots in the liner of the gasifier.
He is working with Eastman Chemical Co. to develop a baseline requirement matrix for refractory health monitoring to guide the design and fabrication of the new sensor. Together, they will build a laboratory-scale double-layer refractory furnace to demonstrate the distribution of high temperatures between the two layers and prove the sensor’s ability to accurately detect hot spots, Wang said.
Finally, the Electric Power Research Institute is funding a four-year study by the photonics center to investigate the validity of two approaches to monitoring and detecting hydrogen and acetylene.
The use of fiber optic sensors for online detection of gas in transformers is useful because they have an “inherent immunity to electromagnetic interference, high sensitivity, light weight and small size,” Wang said.
In this project, Virginia Tech will develop a more economical method for online dissolved gas detection. The key is that this method does not require oil sampling and provides real-time data about transformer health.
Power transformer failures often are caused by dielectric breakdowns that can be triggered by a surge in various chemical gases such as acetylene and hydrogen dissolved in the transformer oil. Dissolved gas detection is thus an important method to learn the health condition of a transformer. The detection currently is handled manually by a process called Dissolved Gas Analysis (DGA), a routine procedure in the power industry. However, DGA is an expensive method involving oil sampling, shipping and laboratory analysis. It often takes days for the measurement results to be obtained. Although DGA can be installed on site and access the transformer oil with a connection port, the cost is still high.
For more information, visit: photonics.ece.vt.edu
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