Publications de Dan-Cristian Tomozei

Load Balancing Video Clients in Enterprise Wireless Networks

Sergio Mena, Lorenzo Granai, Dan-Cristian Tomozei, Aswin Suresh

Given the increasing popularity of real-time video communication over enterprise wireless networks, ensuring good quality of experience is becoming critical. A common problem in such networks is that the clients typically adopt the strategy of associating ...

IEEE2018

AC OPF in radial distribution networks – Part II: An augmented Lagrangian-based OPF algorithm, distributable via primal decomposition

Jean-Yves Le Boudec, Mario Paolone, Dan-Cristian Tomozei, Konstantina Christakou

In the first part of this two-part paper we show that the branch-flow convexification of the OPF problem is not exact and that the ADMM-based decomposition of the OPF fails to converge in specific scenarios. Therefore, there is a need to develop algorithms ...

Elsevier2017

AC OPF in radial distribution networks – Part I: On the limits of the branch flow convexification and the alternating direction method of multipliers

Jean-Yves Le Boudec, Mario Paolone, Dan-Cristian Tomozei, Konstantina Christakou

The optimal power-flow problem (OPF) has always played a key role in the planning and operation of power systems. Due to the non-linear nature of the AC power-flow equations, the OPF problem is known to be non-convex, therefore hard to solve. During the la ...

Elsevier2017

Attribution Mechanisms for Ancillary Service Costs Induced by Variability in Power Delivery

Jean-Yves Le Boudec, Dan-Cristian Tomozei, Nicolas Gabriel Gast

The increased penetration of renewable energy sources in existing power systems has led to necessary developments in electricity market mechanisms. Most importantly, renewable energy generation is increasingly made accountable for deviations between schedu ...

IEEE Institute of Electrical and Electronics Engineers2016

iPRP - the Parallel Redundancy Protocol for IP Networks: Protocol Design and Operation

Jean-Yves Le Boudec, Dan-Cristian Tomozei, Miroslav Popovic, Maaz Mashood Mohiuddin

Reliable packet delivery within stringent delay-constraints is of paramount importance to mission-critical computer applications with hard real-time constraints. Because retransmission and coding techniques counteract the delay requirements, reliability ma ...

Institute of Electrical and Electronics Engineers2016

Worst-Case Optimal Battery Filling Policies With Constrained Adjustable Service

Jean-Yves Le Boudec, Dan-Cristian Tomozei

We study battery filling policies with hard deadlines when the supply of energy can be modulated. This occurs for example with an electric plug-in vehicle using an adjustable electricity service for charging; such a service is offered in some countries as ...

Institute of Electrical and Electronics Engineers2015

iPRP: Parallel Redundancy Protocol for IP Networks

Jean-Yves Le Boudec, Dan-Cristian Tomozei, Miroslav Popovic, Maaz Mashood Mohiuddin

Reliable packet delivery within stringent delay constraints is of primal importance to industrial processes with hard real-time constraints, such as electrical grid monitoring. Because retransmission and coding techniques counteract the delay requirements, ...

2015

Real-Time State Estimation of the EPFL-Campus Medium-Voltage Grid by Using PMUs

Sidi-Rachid Cherkaoui, Jean-Yves Le Boudec, Mario Paolone, Teklemariam Tsegay Tesfay, Dan-Cristian Tomozei, Styliani Sarri, Paolo Romano, Miroslav Popovic, Marco Pignati, Lorenzo Zanni, Sergio Barreto Andrade, Maaz Mashood Mohiuddin, German Dario Flores Ponce

We describe the real-time monitoring infrastructure of the smart-grid pilot on the EPFL campus. We experimentally validate the concept of a real-time state-estimation for a 20 kV active distribution network. We designed and put into operation the whole inf ...

2015

Primary Voltage Control in Active Distribution Networks via Broadcast Signals: The Case of Distributed Storage

Jean-Yves Le Boudec, Mario Paolone, Dan-Cristian Tomozei, Konstantina Christakou, Maryam Bahramipanah

In this paper, we consider an active distribution network (ADN) that performs primary voltage control using real-time demand response via a broadcast low-rate communication signal. The ADN also owns distributed electrical energy storage. We show that it is ...

Ieee-Inst Electrical Electronics Engineers Inc2014

GECN: Primary Voltage Control for Active Distribution Networks via Real-Time Demand-Response

Jean-Yves Le Boudec, Mario Paolone, Dan-Cristian Tomozei, Konstantina Christakou

Demand response (DR) has traditionally targeted peak shaving for the optimal allocation of electricity consumption on a time scale that ranges from minutes to hours. However, with the availability of advanced monitoring and communication infrastructure, th ...

Ieee-Inst Electrical Electronics Engineers Inc2014

Optimal Generation and Storage Scheduling in the Presence of Renewable Forecast Uncertainties

Jean-Yves Le Boudec, Dan-Cristian Tomozei, Nicolas Gabriel Gast

The increase in the penetration of wind in the current energy mix is hindered by its high volatility and poor predictability. These shortcomings lead to energy loss and increased deployment of fast-ramping generators. The use of energy storage compensates ...

Ieee-Inst Electrical Electronics Engineers Inc2014

On the Necessity of Traffic Shaping for PMU Measurement Data Streams

Jean-Yves Le Boudec, Dan-Cristian Tomozei, Peng Gao, Miroslav Popovic

We study the communication network of an on-campus active distribution network (ADN) that comprises phasor measurement units (PMUs) connected to medium-voltage transformers. Within stringent time delays and with minimal loss the PMUs periodically transfer ...

2013

Impact of Storage on the Efficiency and Prices in Real-Time Electricity Markets

Jean-Yves Le Boudec, Dan-Cristian Tomozei, Nicolas Gabriel Gast

We study the effect of energy-storage systems in dynamic real-time electricity markets. We consider that demand and renewable generation are stochastic, that real-time production is affected by ramping constraints, and that market players seek to selfishly ...

ACM2013

Efficient Computation of Sensitivity Coefficients of Node Voltages and Line Currents in Unbalanced Radial Electrical Distribution Networks

Jean-Yves Le Boudec, Mario Paolone, Dan-Cristian Tomozei, Konstantina Christakou

The problem of optimal control of power distribution systems is becoming increasingly compelling due to the progressive penetration of distributed energy resources in this specific layer of the electrical infrastructure. Distribution systems are, indeed, e ...

Ieee-Inst Electrical Electronics Engineers Inc2013

Stability of a Stochastic Model for Demand-Response

Jean-Yves Le Boudec, Dan-Cristian Tomozei

We study the stability of a Markovian model of electricity production and consumption that incorporates production volatility due to renewables and uncertainty about actual demand versus planned production. We assume that the energy producer targets a fixe ...

2013

A Demand-Response Calculus with Perfect Batteries

Jean-Yves Le Boudec, Dan-Cristian Tomozei

We consider an electricity consumer equipped with a perfect battery, who needs to satisfy a non-elastic load, subject to external control signals. The control imposes a time-varying upper-bound on the instantaneous energy consumption (this is called ``Dema ...

2012

Demand Response Using Service Curves

Jean-Yves Le Boudec, Dan-Cristian Tomozei

We propose an alternative approach, based on ``service curves", which uses the following two ingredients. (1) The rate at which a consumer may draw power from the grid may be controlled by real time signals. Typical concerned devices would be heating syste ...

2011

Satisfiability of Elastic Demand in the Smart Grid

Jean-Yves Le Boudec, Dan-Cristian Tomozei

We study a stochastic model of electricity production and consumption where appliances are adaptive and adjust their consumption to the available production, by delaying their demand and possibly using batteries. The model incorporates production volatilit ...

2011