Jacques Lobry | University of Mons (original) (raw)

Papers by Jacques Lobry

IEEE Transactions on Magnetics, 2021

A new hybrid finite element method–boundary element method (FEM–BEM) scheme is proposed for the s... more A new hybrid finite element method–boundary element method (FEM–BEM) scheme is proposed for the solution of the nonlinear 2-D Laplace problem. The novelty is an original approach of the BEM where the domain integrals are eliminated at the discrete level by using the FEM approximation of the fundamental solution at every node of the related mesh in the linear regions. The implementation of this FEM-Green approach requires less computational burden than the standard BEM. The coupling with FEM is straightforward and appears to be more natural. The validity of the method is examined through numerical examples.

This paper analyses with a probabilistic approach the massive integration of distributed photovol... more This paper analyses with a probabilistic approach the massive integration of distributed photovoltaic (PV) generation sources in low voltage (LV) networks, the main impact being the increased overvoltage risk at nodes located close to PV units. The Distribution System Operator (DSO) needs to quantify this overvoltage risk and to accurately estimate and locate the probabilities of such events. By doing so, it will be able to design adequate mitigation solutions and to increase the PV hosting capacity of the network. Given the uncertainty of energy exchange in LV networks, due to the time varying PV injection and random character of the consumption loads, probabilistic models are highly recommended for their analysis. This paper presents a probabilistic framework, based on real smart metering (SM) measurements in order to simulate LV networks with distributed PV generation. The presented framework can either analyse such networks as perfectly balanced systems or consider the existing ...

This study evaluates the performance of the Voltage Based Droop (VBD) control in mitigating overv... more This study evaluates the performance of the Voltage Based Droop (VBD) control in mitigating overvoltage due to photovoltaic units (PV) in Low Voltage (LV) networks. The benefit of this primary control of PV inverters, with respect to the on-off oscillations, the voltage level and the captured energy in LV networks, has been already demonstrated with deterministic “worst case” approaches on small networks and for restricted time periods. These approaches do not consider the intermediate network operation states but only the extreme ones (lowest expected consumption - highest PV generation) and they often lead to over dimensioned and costly technical solutions. In this paper, the P/V control (implemented in the VBD control) is evaluated with a probabilistic analysis framework that considers the time fluctuation of the PV generation and of the voltage at the MV/LV transformer as well as the randomness of the consumption loads. The nodal statistical profiles of these fluctuating paramet...

2016 International Conference on Probabilistic Methods Applied to Power Systems (PMAPS), 2016

Lately distribution utilities worldwide have been incentivized to reduce operating expenses that ... more Lately distribution utilities worldwide have been incentivized to reduce operating expenses that have severely increased with the integration of distributed generation. Enabling demand flexibility in the low voltage network seems a promising means at this direction. Given the current (low) electricity prices and the stochasticity of distributed generation and loads, this paper explores whether a capacity-based distribution tariff that rewards low power withdrawal during peak hours could incentivize small end-users to participate in demand side management. The assessment deploys a pseudo-sequential Monte Carlo simulation that uses quarter-hourly energy measurements and accounts for network constraint management. The presented case study highlights that a coordinated technical implementation is required, both during peak and non-peak periods, for not stressing LV network operation with the integration of flexibility. The potentially generated revenue for end-users, thanks to their response to the considered distribution tariff, results sufficiently motivating for engaging them in flexibility actions.

2016 IEEE International Energy Conference (ENERGYCON), 2016

This paper applies a long term network observability analysis for investigating the potential con... more This paper applies a long term network observability analysis for investigating the potential contribution of photovoltaic (PV) inverters to the mitigation of voltage unbalance in low voltage (LV) feeders. For this purpose, a probabilistic offline state estimation algorithm is used, which simulates the time-varying action of local voltage (magnitude and unbalance) control schemes. The paper focuses on a control scheme that acts resistively towards the negative- and zero-sequence voltage components without modifying the total nodal injected power (three phase damping control scheme) For this long term evaluation, feeder- and user-specific smart metering (SM) data are used. The volatile character of PV generation and loads is modelled on a 15-min time scale. As a case study, a real LV feeder with distributed PV generation and long-term user-specific SM measurements is simulated. The three phase damping control results to be more advantageous compared with currently applied voltage control schemes.

Electric Power Systems Research, 2015

MATLAB for Engineers - Applications in Control, Electrical Engineering, IT and Robotics, 2011

ISRN Renewable Energy, 2012

An original nonsequential Monte Carlo simulation tool is developed. It permits to compute the opt... more An original nonsequential Monte Carlo simulation tool is developed. It permits to compute the optimal dispatch of classical thermal generation in order to minimize pollutants emissions in presence of wind power and under operating constraints.

European Transactions on Electrical Power, 2010

In this paper, a general strategy is proposed in order to introduce in a realistic way wind power... more In this paper, a general strategy is proposed in order to introduce in a realistic way wind power into a HLII (bulk power system) nonsequential Monte Carlo adequacy study with economic dispatch. By use of the implemented solution, wind power can consequently be confronted to operational constraints related to high‐powered thermal units, nuclear parks or cogeneration. Moreover, in order to optimize the large‐scale integration of wind power production, the required reinforcements on a given electrical grid can also be evaluated on basis of the presented developments. The elaborated strategy can practically be applied to every kind of nonsequential Monte Carlo approach used to technically analyze a given transmission system. In the context of this work, the proposed solution has been implemented into the simulation tool Scanner© (property of Tractebel Engineering – Gaz de France – Suez company). Finally, in order to point out the efficiency and the usefulness of the proposed wind power...

Problems that present geometrical symmetry are often met in domain types methods like the Boundar... more Problems that present geometrical symmetry are often met in domain types methods like the Boundary Element Method (BEM). In order to reduce the computation times, symmetry can be taken into account thanks to a rationale called the Group Representation Theory. The method consists in reducing an original problem into a family of smaller ones, the global solution is obtained from superposition. In this paper, we propose the implementation of the BEM for the 2-D Magnetostatics where the Poisson's equation is defined on symmetrical non-homogeneous regions. The non-abelian case is considered. The theory is developed and the example of an induction motor is presented.

International Journal of Applied Ceramic Technology, 2013

Electric Vehicles - Modelling and Simulations, 2011

Mathematics

A new finite element method/boundary element method (FEM/BEM) scheme is proposed for the solution... more A new finite element method/boundary element method (FEM/BEM) scheme is proposed for the solution of the 2D magnetic static and quasi-static problems with unbounded domains. The novelty is an original approach in the treatment of the outer region. The related domain integral is eliminated at the discrete level by using the finite element approximation of the fundamental solutions (Green’s functions) at every node of the related mesh. This “FEM-Green” approach replaces the standard boundary element method. It is simpler to implement because no integration on the boundary of the domain is required. Then, the method leads to a substantially reduced computational burden. Moreover, the coupling with finite elements is more natural since it is based on the same Galerkin approximation. Some examples with open boundary and nonlinear materials are presented and compared with the standard finite element method.

International Journal of Applied Electromagnetics and Mechanics

International Journal of Electrical Engineering & Education

This paper describes a project in which students must implement two advanced control schemes for ... more This paper describes a project in which students must implement two advanced control schemes for a voltage-fed inverter induction motor drive, namely vector control and direct torque control, using a dSPACE platform and a Matlab/Simulink environment. With this platform, students can focus on these two control schemes without spending too much time on details concerning the implementation of the control algorithms on the board.

International Journal of Electrical Engineering Education

Renewable Energy and Power Quality

Renewable Energy and Power Quality Journal