Search results for "Tribute"
showing 10 items of 1455 documents
Charging Electric Vehicles Using Opportunistic Stopovers
2017
The diffusion of electric vehicles asks for efficient energy replenishment, which requires geographical and temporal coordination of shared charging resources. We introduce a novel charging methodology that exploits users’ opportunistic mobility. This paper focuses on vehicle stopovers detecting potential charg- ing opportunities. Our mobility-assisted methodology protects users privacy and permits a hybrid centralized/distributed ap- proach avoiding clashes with other potential users. A preliminary analysis on our charging system, obtained with mobility data from the field, shows that among the available charging stations, some are more relevant and have a key role in serving electric vehi…
A distributed control system for citric fruits conservation and maturation based on CAN and Internet networks
2007
In citric fruits conservation and maturation systems it is very important to have precise information about parameters that indicate the citric fruit state. This information allows computing the appropriate control actions in order to achieve an optimum controlled citric fruit conservation and maturation. Last technological advances must be also used in this agriculture field to forget the rudimentary control systems that are being used at the present time. This paper describes a new distributed control system devoted to control citric fruits cold chambers that applies the last computer and electronics techniques. It is structured over different communication networks, making possible a rem…
Cyber Security for Wireless Semantic (SCADA/DCS) Systems
2016
International audience; Supervisory Control and Data Acquisition and Distributed Control Systems named (SCADA/DCS) have played a key role in the design of modern power smart applications, particularly in the automatic management of real time energetic platforms. In this work, we present a semantic cyber security vulnerabilities add to classic one, with the use of semantic embedded application in smart devices in semantic wireless (SCADA/DCS) systems, focusing on the semantic attacks. In this work, we present a new security semantic wireless protocol as a secure communication support for these modern semantic wireless systems named (ZIGBEE/SOAP/SECURITY), obtained by the combination between …
Impact of integrating photovoltaic based DG on distribution network harmonics
2017
The process of integrating various distributed generation (DG) technologies in power system networks is increasing rapidly in the recent years. One major concern about the integration of DGs is their impact on network harmonics. The aim of this paper is to investigate the effects caused by the integration of photovoltaic DG in distribution networks on system harmonics. The penetration level, number of DG units, and their location are used as parameters in order to verify the effects of DG on system harmonics. Moreover, a study of single and double tuned filters is conducted as harmonics mitigation techniques. Detailed simulations using Matlab/Simulink are inserted in order to explain and ve…
Impedance estimation of FEA's grid in fiji islands by V-I measurement by using the synchronous reference frame-PLL
2017
In recent years there has been a significant increase in distributed renewable energy generation feeding into the grid, with resulting detriment of the stability of the network, since present networks have not been designed for this purpose. To feed-in these renewable energy sources with minimum impact, it is essential to know a few grid parameters (voltage, current, grid impedance) at the point in which power supply is convenient. For this purpose in this paper an algorithm is proposed to obtain the estimated network impedance. This algorithm operates in time domain by a synchronous reference coordinate transformation, it requires only the measurement of the phase voltage with no-load and …
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…
Control of solid-state fault current limiter for DG-integrated distribution systems
2017
Fault current limier (FCL) is a device that limits the system current under fault conditions without disconnecting the system and affecting the power system protection components such as circuit breakers. Many types of FCLs have been proposed to limit the magnitude of the fault current. Solid-state fault current limiters (SSFCLs) can limit the peak value of the fault current by applying several methods, such as controlling the system impedance or controlling the voltage that appears across the fault. In this paper, a new control scheme for the SSFCL circuit is presented. The control method is based on controlling the duty cycle of solid state switches to control the rms value of the system …
Flexible power converters for the fault tolerant operation of Micro-Grids
2010
The progressive penetration level of Distributed Generation (DG) is destined to cause deep changes in the existing distribution networks no longer considered as passive terminations of the whole electrical system. A possible solution is the realization of small networks, namely the Micro-Grids, reproducing in themselves the structure of the main production and distribution of the electrical energy system. In order to gain an adequate reliability level of the microgrids the individuation and the management of the faults with the goal of maintaining the micro-grid operation (fault tolerant operation) is quite important. In the present paper flexible power converters and a companion control al…
A New Solution for Low-Voltage Distributed Generation Interface Protection System
2015
In this paper, a new solution is proposed for the remote monitoring and control of distributed generators (DGs) and energy storage systems (ESSs) connected to low-voltage distribution networks. The proposed system fulfills the in-force standard requirements for the connection of DGs to the utility grid. Moreover, it allows implementing some enhanced functions for the remote control of inverters of DGs and ESSs, not only in terms of disconnection but also in terms of voltage regulation and power shuttering. The proposed solution is based on a new interface protection system and a dedicated secondary substation concentrator, which allows the communication between the distributed system operat…
A multi-agent system reinforcement learning based optimal power flow for islanded microgrids
2016
In this paper, a distributed intelligence algorithm is used to manage the optimal power flow problem in islanded microgrids. The methodology provides a suboptimal solution although the error is limited to a few percent as compared to a centralized approach. The solution algorithm is multi-agent based. According to the method, couples of agents communicate with each other only if the buses where they are located are electrically connected. The overall prizing system required for learning uses a feedback from an approximated model of the network. Based on the latter, a distributed reiforcement learning algorithm is implemented to minimize the joule losses while meeting operational constraints…