Research interests

I am working in the field of electric power system engineering. My activities deal with the following topics of transmission or distribution networks:
  • dynamics, control and stability, in particular voltage stability
  • real-time security assessment
  • wide-area monitoring
  • numerical simulation of dynamics of large-scale power systems.

Current research topics

  • Voltage stability

    short- and long-term aspects, wide-area monitoring and control, early detection of instability conditions from synchronized phasor maeasurements, emergency control (e.g. modified tap changer control, load shedding, etc.), fast time simulation for voltage security assessment
    with Mevludin Glavic

  • Domain-decomposition, localization, time-scale exploitation and parallel processing techniques applied to time-domain simulations in phasor mode

    for application to large-scale systems, in particular the simulation of combined Transmission & Distribution systems
    with Petros Aristidou

  • Hybrid power system simulation combining phasor-mode and electromagnetic transients models

    multirate approach to take advantage of the high speed of phasor-mode simulation and the higher accuracy of EMT models
    with Frédéric Plumier

  • Tracking state estimation combining conventional SCADA measurements with a limited number of synchrophasor measurements

    The aim is to follow some of the dynamics of the network state (bus voltage phasors). To avoid time skew effects, only the SCADA measurements received since the last execution of the estimator are processed. To ensure observability, estimated SCADA measurements are used as pseudo-measurements. The procedure includes a prediction, an innovation analysis and a correction step.
    with Boris Alcaide and Mevludin Glavic

  • Robustness of future AC/DC transmission systems.

    Advanced control and supervisory schemes for the future multi-terminal High Voltage Direct Current (HVDC) networks, used as overlay transmission grids and providing frequency support among asynchronous AC systems.
    Impact on the operation of AC systems of large disturbances affecting the HVDC grids, and the corresponding defence plans
    with Lampros Papangelis
    in collaboration with Patrick Panciatici and Marie-Sophie Debry from R&D dept. of RTE (France)
    with the help of Petros Aristidou (ULg) and Xavier Guillaud (Ecole Centrale de Lille, France)

  • Real-time control of Medium-Voltage distribution networks

    Centralized control schemes acting on the Distributed Generation (DG) units connected to the Medium-Voltage (MV) grid to keep voltages in the desired range and currents below the thermal limits. Approaches inspired of Model Predictive Control. Extension to control of flexible loads.

    • within the context of the GREDOR project
      with Hamid Soleimani Bidgoli
    • Extension to support of the transmission system in critical voltage situations.
      with Gustavo Valverde and Petros Aristidou
  • State estimation in MV distribution networks

    within the context of the GREDOR project, a new formulation of state estimation is developed and tested, including demand and generation states
    with Patricia Rousseaux and Mevludin Glavic
    and the collaboration of our colleagues from UMons

  • Control of PhotoVoltaic units in Low-Voltage distribution networks to correct abnormal voltages

    with Petros Aristidou, Frédéric Olivier and Damien Ernst

GREDOR project supported by Walloon region

Rethinking the Walloon distribution systems to host more renewable energy sources

The willingness to increase the penetration of renewable energy sources, the evolution of the consumption pattern (due to e.g. electric vehicles), and other mutations in the electricity sector will soon push the distribution systems towards their operation limits. Thermal overloads of equipment, under-voltages and over-voltages are likely to be experienced more often. Classical approaches would lead to either reinforcing the network or preventing the deployment of renewable distributed generation. Active distribution network management is an attractive alternative, in so far as those stressed operating conditions prevail for limited periods of time. It consists of acting on distributed generation sources (and, in the future, on flexible loads) to mitigate those problems. This allows postponing costly network investments while hosting more renewable energy sources.

The GREDOR project addresses those planning, operational planning and real-time challenges. It is funded by the Public Service of Wallonia, Department of Energy and Sustainable Building, and coordinated by the University of Liège (ULg) and encompasses academic and industrial partners.

Projects supported by European Commission

I took an active part in the following collaborative projects sponsored by European Commission:

  • OMASES (5th framework, coordinated by ALSTOM): in collaboration with the National Technical University of Athens (Prof. Costas Vournas), a real-time Voltage Security Assessment (VSA) has been implemented at the national control centre of the Hellenic Transmission System Operator (now IPTO). In response to voltage stability concerns in the Greek system, OMASES has been extended through a trilateral collaboration to further develop and maintain this VSA tool, which is still in operation
  • The PEGASE project (FP7 framework, coordinated by Tractebel Engineering) has produced new tools for the real-time control and operational planning of the Pan-European transmission network. New algorithms able to process large-scale models have been developed for state estimation, Dynamic Security Assessment (DSA), steady-state optimization (optimal power flow) and dispatcher training simulator. The ULg team contributed to the first three topics. D. Fabozzi and I worked on devising time simulation algorithms for DSA purposes, allowing to balance between accuracy and speed of execution. This involved interactions with RTE (France) and Tractebel Engineering, two among the 22 partners of the PEGASE consortium. PEGASE_logo