Real-time Data Enables Better Voltage Stability in Electric Power Generation
Researchers at the University of Tennessee-Knoxville (UTK) have developed anew approach to real time monitoring and control of voltage in electric power generation that improves the ability of operators to anticipate unstable and dangerous conditions. The project is an initiative of the Engineering Research Center (ERC) for Ultra-wide-area Resilient Electric Energy Transmission Network (CURENT), which is co-funded by the National Science Foundation and the Department of Energy and headquartered at UTK.
This research is part of CURENT’s effort to assist in the redevelopment of a nation-wide or continent-wide transmission grid that is fully monitored and dynamically controlled in realtime. Voltage stability assessment (VSA) is a key function in power system operations. As a transmission network operates closer to its loading limit – e.g., in an area (load center)where maximum power is consumed – maintaining voltage stability is extremely important. However, traditional modeling and simulation VSA approaches may not reflect actual conditions.The new UTK VSA approach uses realtime measurement of actual conditions to provide information that is more reliable.
Computer simulation-based VSA tools are available to assist operators in monitoring and controlling voltage stability. However, these tools rely highly on the acceptance that complex modeling of generation, load, and transmission facilities yields real-world outcome. Inaccurate models may result in inaccurate VSA results, leading operators to make incorrect decisions and increase the risk of voltage collapse. The UTK team’s measurement-based VSA method monitors and controls voltage of a load center area, whose electricity is fed by multiple tie lines. The stability margin of each tie line can be calculated directly from the measurement data taken on tie lines. Thus, the tie line with the smallest margin is identified as the most critical one, indicating where voltage instability might originate and preventive voltage control should be conducted. Thismeasurement-basedVSAcomplements the traditional simulation-based VSA to provide comprehensive voltage stability monitoring and control. It has been validated by Northeast Power Coordinating Council(NPCC) large-scale testing and the hardware testbed developed by CURENT.