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MPEL Seminar

Real-time, Measurement-based Identification of Voltage Instability Onset

Constantine (Costas) VournasProfessor (Retired)National Technical University of Athens
Michigan Memorial Phoenix Laboratory, Suite 2000Map


This presentation will start with a short introduction to Voltage Stability concepts followed by an overview of Global vs Local Voltage Instability Detection approaches including a critical review of Impedance matching based methods and their limitations. Then the LIVES method (Local Identification of Voltage Emergency Situations) will be shortly presented and shown to provide a local detection of global stability by monitoring the LTC voltage recovery. The extension of this method to the New LIVES Index (NLI) that is based on local measurements at a transmission corridor will follow. This method is based on monitoring the change of transferred active power relative to the increase of apparent conductance (ΔP/ΔG). A particular application to obtain a transmission-line Relay-Based Index will be also discussed. All methods will be validated using simulation of an IEEE test system for Voltage Security Assessment.


Constantine (Costas) Vournas received the Diploma of Electrical and Mechanical Engineering from the National Technical University of Athens (NTUA) in 1975, the M.Sc in Electrical Engineering from the University of Saskatchewan, Saskatoon, Canada in 1978, and the NTUA Doctor of Engineering degree in 1986. He is Professor (retired 2019) in the School of Electrical and Computer Engineering of NTUA. He has published more than 150 papers in International Journals and Conferences and has co-authored the book “Voltage Stability of Electric Power Systems”. His research interests are in the area of power system dynamics, stability and control and include voltage stability and security analysis, wind generator integration in power systems, novel control applications in the distribution and transmission grid, as well as the effect of deregulation on power system operation and control. He is Fellow of IEEE since 2005, member of CIGRE, Editor of Electric Power System Research International Journal. He was Chair of the IEEE/PES Power Tech Steering Committee (2007-2019), Region 8 Representative on the IEEE Power and Energy Society (PES) Governing Board (2011-2014) and is currently Chairman of the PES Power Systems Dynamic Performance Committee.

Sponsored by



Judi Jones(734) 763-8557

Faculty Host

Ian HiskensProfessorUniversity of Michigan Department of EECS