Virginia Tech has launched the first network ever deployed to monitor the entire U.S. power grid as well as the world’s first frequency monitoring system using the internet and the Global Positioning System (GPS). The system uses inexpensive frequency recording units (FRU) that are plugged into standard 110V outlets at various university and office locations nationwide.
An on-line dynamic frequency map provided by the Virginia Tech FNET system, helps researchers, operators, and students understand, monitor, and measure the power grid in real time.
TCalled FNET (frequency monitoring network), the real-time, wide-area, synchronized measurement system is based on the concept that system frequency remains constant regardless of voltage level. However, when a significant disturbance occurs, the frequency varies in time and space exhibiting identifiable wave characteristics. As a result, by constantly measuring frequency, system operators can monitor system status and detect disturbances.
FNET uses the internet for wide area data gathering and transmission, and taps GPS time synchronization for precise data analysis. The system is based on the phasor measurement unit technology (PMU) developed at Virginia Tech by Arun Phadke.
Modeling the power grid as a continuum with geographic data is providing researchers with new understanding of how disturbances propagate throughout the system in a electromechanical wave dispersion. The technique, developed by James Thorp’s team when he was at Cornell, provides global behavior analysis not available with conventional discrete system modeling.
FNET’s unique feature is its ability to provide accurate measurements without needing to be installed at high-voltage substations. By eliminating the time and high costs involved with substation deployment, FNET costs a small fraction of what would be required to get global dynamic frequency information using other technology. The installed cost of one PMU last year was more than $80,000 according to the Tennessee Valley Authority (TVA), whereas an FNET unit was only 1-3 percent of that amount.
Since the units do not need to be installed at substations, FNET provides an independent observation system of the US power grids and can contribute to the homeland security monitoring system. FNET can be used for operational and research purposes. The system can provide information for analyzing the underlying causes of cascading events. System operators can detect system disturbances, and researchers can use FNET to verify system models for better understanding the theory of system oscillations. Yilu Liu has led development of the project, assisted by Richard Conners, Phadke, Virgilio Centeno, and Lamine Mili.