My general area of research is electric power system engineering.

The focus is on large systems for the generation, transmission and distribution of electrical energy, more precisely their dynamics, stability and control as well as the analysis of their security.

More specifically, my ongoing or recent research pertains to the following topics :

Numerical methods for the time simulation of large-scale power systems

    Fast, simplified time-domain simulation of long-term dynamics. Application to voltage stability analysis and control.

    Shared-memory parallel processing of detailed time-domain simulation under the phasor approximation.

    Hybrid simulation of Electro-magnetic transients and phasor-mode models.

Real-time corrective control of power systems in emergencies

    Early detection of a system evolving towards instability and automatic remedial actions.

    Application to voltage instability.

System monitoring and state estimation

    Combined used of SCADA and PMU measurements to track the changing network operating point at high rate

AC/DC systems

    Modelling and control of AC/DC Voltage Source Converters.

    AC system frequency support from HVDC links or grids.

    Control of future multi-terminal DC grids.

    Control of future off-shore wind power hubs (with low inertia).

Active distribution networks

    Control of dispersed generation units at distribution level to support voltages of the transmission system.

    Coordinated control of dispersed generation units to correct abnormal voltages and clear contingencies in the distribution grid.

    Dynamic equivalents of active distribution networks for use in large-disturbance dynamic simulations of the transmission system.

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