Raphael Caire

Radial Network Reconfiguration Using Genetic Algorithm Based on the Matroid Theory

This paper deals with distribution network (DN) reconfiguration for loss minimization. To solve this combinatorial problem, a genetic algorithm (GA) is considered. In order to enhance its ability to explore the solution space, efficient genetic operators are developed. After a survey of the existing DN topology description methods, a theoretical approach based on the graph and matroid theories (graphic matroid in particular) is considered. These concepts are used in order to propose new intelligent and effective GA operators for efficient mutation and crossover well dedicated to the DN reconfiguration problem. All resulting individuals after GA operators are claimed to be feasible (radial) configurations. Moreover, the presented approach is valid for planar or nonplanar DN graph topologies and avoids tedious mesh checks for the topology constraint validation. The proposed method is finally compared to some previous topology coding techniques used by other authors. The results show smaller or at least equal power losses with considerably less computation effort.

Possibilistic Evaluation of Distributed Generations Impacts on Distribution Networks

In deregulated power systems, the distribution network operator (DNO) is not responsible for investment in distributed generation (DG) units, and they are just concerned about the best architecture ensuring a good service quality to their customers. The investment and operating decisions related to DG units are then taken by entities other than DNO which are exposed to uncertainty. The DNO should be able to evaluate the technical effects of these uncertain decisions. This paper proposes a fuzzy evaluation tool for analyzing the effect of investment and operation of DG units on active losses and the ability of distribution network in load supply at presence of uncertainties. The considered uncertainties are related to load values, installed capacity, and operating schedule of DG units. The proposed model is applied on a test system and also a real French urban network in order to demonstrate its functionality in evaluating the distribution expansion options.

A Novel Hybrid Network Architecture to Increase DG Insertion in Electrical Distribution Systems

Distribution networks will experience a deep mutation concerning their planning and operation rules due to the expected increase of distributed generation (DG) interconnection to the grid. Indeed, the opening of the electricity market or the growing global concern for environmental issues will lead to a massive development of DGs. Yet, a too large amount of DGs could raise technical problems on distribution networks which have not been planned to operate with bi-directional power flow. The existing solutions to solve marginal DG connections could be no longer relevant. The distribution network definitely has to evolve towards a smarter and more flexible network. Two possible ways to reach this goal are through new architectures and developing intelligent systems. This paper focuses on new architectures and operating modes. The traditional radial distribution network could accept more DGs by introducing appropriately specific loops. A new hybrid structure enabling the coexistence of the radial and meshed operation is proposed. It is equipped with autonomous circuit-breakers and automated switches that improve its reliability. A heuristic algorithm is also proposed to build this new architecture while ensuring the equality of consumers with respect to the continuity of service and while minimizing the global cost.

Neural Networks to Improve Distribution State Estimation—Volt Var Control Performances

Distribution systems must be ready to face upcoming technical and economic constraints: increase of Distributed Generation (DG) connections, changes in network losses and voltage profiles, among others. In this context, new centralized automation functions in distribution system control centers are needed in order to ensure the control of both distribution network and connected DGs. Consequently, state estimators need to be developed for future distribution systems to assess the networks state in real time, i.e., 10 minutes typical time frame, based on real, pseudo-, and virtual measurements. Such state estimation functions are widely used for transmission systems but cannot be transposed directly into distribution systems. Indeed, one of the main issues is the lack of sensors in the distribution network, requiring additional load models to solve observability issues. These load models (also called pseudomeasurements) are usually active and reactive power models at medium to low voltage (MV/LV) substations using often very inaccurate information from historical database or other estimated load curves, for instance. The scale of these errors makes the estimation of all variables in the distribution network difficult. This paper proposes a pseudomeasurement estimation using neural networks in order to improve the results of a distribution state estimator (DSE), used as inputs to a centralized Volt and Var control function.

Towards a common model for studying critical infrastructure interdependencies

The security of critical infrastructures, such as power systems, telecommunication networks, information facilities or even emergency and financial services, is a major aspect for our modern societies. One of the main threats is the growing interdependency between them. Failure in one infrastructure may cascade on others. In many infrastructures, it is mainly caused by the increasing complexity of operating constraints. In order to improve the overall security encompassing power and ICT and issue pertinent guidelines or regulations, it is first needed to better understand their interactions and interdependencies in an integrated view. Different tools are then needed: software able to simulate the dynamic or long term stability of coupled-infrastructures and benchmarks with coupled-components. A combined simulator (based on three dedicated software) and a test case were developed to identify the vulnerabilities of a power system caused by interdependencies with communication and information systems. The developed tool demonstrates the effects of failures from an infrastructure to others. To illustrate, the effects of a faulty router in the telecommunication network that cascade in the electrical infrastructure are presented.

Integrated ICT framework for distribution network with decentralized energy resources: Prototype, design and development

Electrical Distribution Systems (EDS) are facing ever-increased complexity due, in part, to fast growing consumer demands and the integration of large amounts of distributed energy resources. The conventional operation modes need to be adapted to the significant changes. With advanced Information and Communication Technology (ICT) infrastructure and sophisticated new functionalities for energy management, “Smart Grid” is becoming the most forward-looking solution to address these facing challenges. Having initiated a conceptual model, architecture, and implementation plan for the system in previous European research projects (CRISP [1] and MICROGRID [2]). A new integrated platform for ICT based distributed control and local management is currently being designed, with the goal of demonstrating the feasibility of these new concepts. The overarching design of coordination and control between the real automation devices and power system components will be carried out with an analogical micro network (μGrid) including real power operation components such as RTUs. Therefore, some high level functions relied on advanced ICT system such as fault management; voltage control and adaptive reconfiguration are developed and tested for this purpose.

Novel architectures and operation modes of distribution network to increase DG integration

Nowadays, distribution networks are facing tremendous challenges. Actually, the opening of the energy market, the wish to preserve the environment and the reduction of fossil energy stocks have lead to use more and more distributed, renewable and local energy resources, such as wind and photovoltaic generators. These generating units are mostly connected to the distribution networks. With the increase of the penetration rate of these generation facilities, the traditional operation as well as planning of the concerned networks may need to evolve. In order to face this situation and offer increased network capabilities to support these new technologies, the distribution network has to switch to a flexible and smart network. To achieve these goals, two research paths are considered: the new architectures and the development of intelligent embedded systems. This paper deals with new architectures and particularly partially meshed distribution networks. It proposes a Monte Carlo algorithm as an efficient tool for analysing and assessing the relationship between grid architecture and DG penetration rate. Simulation results on a real urban French distribution networks have showed the effectiveness of the method with respect to grid planning. Particularly, it has demonstrated that evolving distribution grid architectures towards a partially and adapted meshed structure increases DG penetration level.

Decentralized operating modes for electrical distribution systems with distributed energy resources

Electrical Distribution Systems (EDS) are undergoing some significant changes at various scales and levels. These changes are triggered by several factors such as the event of Distributed Energy Resources (DER) and the need to improve the quality of supply while achieving economical optima. Hence, several research initiatives, technological development and experiments have been launched worldwide to tackle this situation such as “SmartGrids”. This panel deals with some new decentralized operating modes for EDS management with high penetration of DER. These decentralized modes are based on distributing the management system locally and intelligently using advanced Information and Communication Technology (ICT). These concepts are being demonstrated through an experimental platform: an analogical micro network (μGrid). Functions such as fault management and high level of self adaptive architectures are developed for these new modes.

INTEGRAL: ICT-Platform Based Distributed Control in Electricity Grids with a Large Share of Distributed Energy Resources and Renewable Energy Sources

The European project INTEGRAL aims to build and demonstrate an industry-quality reference solution for DER aggregation-level control and coordination, based on commonly available ICT components, standards, and platforms. To achieve this, the Integrated ICT-platform based Distributed Control (IIDC) is introduced. The project includes also three field test site installations in the Netherlands, Spain and France, covering normal, critical and emergency grid conditions.

Test bench for self-healing functionalities applied on distribution network with distributed generators

Increasing complexity of interconnected electricity grids with a high integration level of dispersed generators leads that “business as usual” operating modes and regular devices in distribution networks are not efficient enough to ensure the centralized management of a large amount of information and high-level functionalities (Advanced Distribution Automation-ADA) for future electricity distribution networks. This weakness could be solved by distributing the management system locally and by smartly using advanced Information and Communication Technology (ICT) Systems. This paper is based on the work performed within the European research project INTEGRAL. It presents a new research path to investigate the validation of an active distribution system, with high integration of ICTs, through an reduced scale analogical demonstration network. The analogical (µGrid) construction, which relies on a real French distribution network, is introduced and detailed. Then, the high level ICT systems enabling self-healing functionalities will be presented to explain how Remote Terminal Units (RTUs) and ICT hardware will be coordinated in this µGrid. Finally, the µGrid reduction procedures will be validated in this paper through both static and dynamic simulations.