Search results for " distributed"

Experimental evaluation of an hybrid communication system architecture for smart grid applications

2015

In this paper a new communication system architecture is proposed for the development of a SCADA system which can remotely monitor and control intelligent electronic devices (IEDs) connected to the low voltage distribution networks, i.e low voltage smart meter (SM), interface protection devises (IPS). New distributed metering systems and interface devices, together with a proper communication infrastructure (HiperLAN and narrowband power line communication (NB-PLC) on low voltage network), have been developed to allow monitoring the whole power system and controlling the distributed generators of a Smart Grid also in the presence of harmonic distortions. In this way, the electrical energy d…

Comparison of power quality impact of different photovoltaic inverters- the viewpoint of the grid

2005

This paper presents the results of an experimental analysis performed with the aim of evaluating the effect of many photovoltaic plants on power quality of the grid. Several parameters as voltage and current distortion, flicker, voltage variations at fundamental frequency and power factor have been observed. The measured values have been compared with the limits reported in the standards and, when possibiIe, their dependence on the characteristics of the grid in terms of its impedance has been pointed out.

Computer Aided Optimization Via Simulation Tools of Energy Generation Systems With Universal Small Wind Turbines

2012

This paper considers the general issues in the project and the optimization of energy generation systems using small universal wind turbines, suitable in Distributed Generation (DG) and computer aided optimization for a better exploitation of wind source. Optimization in this field reveal to be more and more important because the local generation and consumption of electrical power, even for grid connected generators can suffers for unevenness of wind source exploitation, also in terms of wrong directions and in not regular wind flows. Computer aided design and optimization of small plants may give significant improvements in the development of the wind source also in accordance with the pr…

Smart renewable generation for an islanded system. Technical and economic issues of future scenarios

2012

The subject addressed in this paper is the analytical study of the transition of an energy generation system for a real MV/LV distribution system from one that is “fuel-based” to a distributed and smart “renewables-based” system. The paper outlines both the technical and the economic issues related to such a transition from one type of system to the other. The study is carried out for a real islanded network located in the Island of Pantelleria (Mediterranean Sea). The results obtained are presented and discussed, putting into evidence the technical, environmental and economic benefits of using smart technologies and renewable energy sources.

Production planning in reconfigurable enterprises and reconfigurable production systems

2005

Reconfigurable enterprises and reconfigurable production systems represent nowadays one of the key responses towards the organisational and manufacturing needs arising in the new era known as mass customization. The paper proposes an Agent Based approach for the production planning activities in reconfigurable enterprises, characterized by complex, articulated and geographically distributed production capacities contended by many product families and composed by reconfigurable production systems that allow quick adjustment of production capacity and functionality consenting to manufacture different products of the same part family.

Hybrid passive and communications-based methods for islanding detection in medium and low voltage smart grids

2013

Islanding condition takes place when a distributed generator (DG) continues to power a part of the grid even if power from electric utility is no longer present. Adverse effects of islanding are power quality deterioration, grid-protection interference, equipment damage, and personnel safety hazards. For these reasons, DG systems must detect an islanding condition and immediately disconnect from the grid (anti-islanding protection). This paper proposes an hybrid solution, for both low voltage (LV) and medium voltage (MV) applications, which makes use of passive and communication-based methods for islanding detection. Among the existing communication technologies, the study is focused on pow…

Implementing the erosion component of a physically based and distributed model (tRIBS). A first application to an experimental basin.

2008

Gigabit Ethernet backbones with active loops

2001

The current standard Ethernet switches are based on the Spanning Tree (ST) protocol. Their most important restriction is that they can not work when the topology has active loops. In fact, the ST protocol selects a tree from the real topology by blocking the links that are not involved in the tree. This restriction produces a network traffic unbalancing behavior saturating those link near the root switch while rest of links will be idle or with a very low utilization. This paper proposes a new transparent switch protocol for Gigabit Ethernet backbones that considerably improves the performance of current ones. The proposed protocol is named ALOR for Active Loops and Optimal Routing. ALOR pr…

Backwards Martingales and Exchangeability

2020

With many data acquisitions, such as telephone surveys, the order in which the data come does not matter. Mathematically, we say that a family of random variables is exchangeable if the joint distribution does not change under finite permutations. De Finetti’s structural theorem says that an infinite family of E-valued exchangeable random variables can be described by a two-stage experiment. At the first stage, a probability distribution Ξ on E is drawn at random. At the second stage, independent and identically distributed random variables with distribution Ξ are implemented.

Scheduling on Two Types of Resources: a Survey

2020

International audience; We study the problem of executing an application represented by a precedence task graph on a parallel machine composed of standard computing cores and accelerators. Contrary to most existing approaches, we distinguish the allocation and the scheduling phases and we mainly focus on the allocation part of the problem: choose the most appropriate type of computing unit for each task. We address both off-line and on-line settings and design generic scheduling approaches. In the first case, we establish strong lower bounds on the worst-case performance of a known approach based on Linear Programming for solving the allocation problem. Then, we refine the scheduling phase …