Application of Wireless Sensor and Actuator Networks to Achieve Intelligent Microgrids: A Promising Approach towards a Global Smart Grid Deployment

Smart Grids (SGs) constitute the evolution of the traditional electrical grid towards a new paradigm, which should increase the reliability, the security and, at the same time, reduce the costs of energy generation, distribution and consumption. Electrical microgrids (MGs) can be considered the first stage of this evolution of the grid, because of the intelligent management techniques that must be applied to assure their correct operation. To accomplish this task, sensors and actuators will be necessary, along with wireless communication technologies to transmit the measured data and the command messages. Wireless Sensor and Actuator Networks (WSANs) are therefore a promising solution to achieve an intelligent management of MGs and, by extension, the SG. In this frame, this paper surveys several aspects concerning the application of WSANs to manage MGs and the electrical grid, as well as the communication protocols that could be applied. The main concerns regarding the SG deployment are also presented, including future scenarios where the interoperability of different generation technologies must be assured

Detection, Characterization and Modeling of Localized Defects and Thermal Breakdown in Photovoltaic Panels from Thermal Images and IV Curves

In this work, a defective commercial module with a rounded IV characteristic is analyzed in detail to identify the sources of its malfunction. The analysis of the module includes thermography images taken under diverse conditions, the IV response of the module obtained without any shadow, and shadowing one cell at a time, as recommended by the IEC 61215 Standard. Additionally, a direct measurement of the IV characteristic and resistance of single cells in the panel has been conducted to verify the isolation between the p and n areas. In parallel, theoretical cell and module behaviors are presented. In this frame, simulations show how cell mismatch can be the explanation to the rounded IV output of the solar panel under study. From the thermal images of the module, several localized hot spots related to failing cells have been revealed. During the present study, thermal breakdown is seen before avalanche breakdown in one of the cells, evidencing a hot spot. Not many papers have dealt with this problem, whereas we believe it is important to analyze the relationship between thermal breakdown and hot spotting in order to prevent it in the future, since hot spots are the main defects related to degradation of modern modules

Energy-aware Cross-level Model for Wireless Sensor Networks

ISBN: 978-1-61208-744-3International audienceIn the design stage, Wireless Sensor Network developers generally need simulation tools to save both time and costs. These simulators require accurate models to precisely describe the network components and behaviours, such as energy consumption. Nevertheless, although the model has grown in complexity over last years, from layered-stack to cross-level, the energy aspects are not yet well implemented. In this paper, we suggest an energy-aware cross-level model for Wireless Sensor Networks. Our modelling approach allows for parameters that belong to different levels to interact with each other and to analyse their impact on energy consumption. To validate this approach, the energy-aware cross-level model for network radiofrequency activities is first provided. The results obtained using suggested scenarios are compared with those collected from a well-known simulator: NS2. Finally, the usefulness of our model in Wireless Sensor Network design process is demonstrated thanks to a case study aimed at comparing and selecting the most energy-efficient wireless link protocol

Methodology to Evaluate WSN Simulators: Focusing on Energy Consumption Awareness

ISBN: 978-1-925953-09-1International audienceNowadays, there exists a large number of available network simulators, that differ in their design, goals, and characteristics. Users who have to decide which simulator is the most appropriate for their particular requirements, are today lost, faced with a panoply of disparate and diverse simulators. Hence, it is obvious the need for establishing guidelines that support users in the tasks of selecting and customizing a simulator to suit their preferences and needs. In previous works, we proposed a generic and novel methodological approach to evaluate network simulators, considering a set of qualitative and quantitative criteria. However, it lacks criteria related to Wireless Sensor Networks (WSN). Thus, the aim of this work is three fold: (i) extend the previous proposed methodology to include the evaluation of WSN simulators, such as energy consumption modelling and scalability; (ii) elaborate a study of the state of the art of WSN simulators, with the intention of identifying the most used and cited in scientific articles; and (iii) demonstrate the suitability of our novel methodology by evaluating and comparing three of the most cited simulators. Our novel methodology provides researchers with an evaluation tool that can be used to describe and compare WSN simulators in order to select the most appropriate one for a given scenario

A Nonlinear Autoregressive Exogenous (NARX) Neural Network Model for the Prediction of the Daily Direct Solar Radiation

The solar photovoltaic (PV) energy has an important place among the renewable energy sources. Therefore, several researchers have been interested by its modelling and its prediction, in order to improve the management of the electrical systems which include PV arrays. Among the existing techniques, artificial neural networks have proved their performance in the prediction of the solar radiation. However, the existing neural network models don't satisfy the requirements of certain specific situations such as the one analyzed in this paper. The aim of this research work is to supply, with electricity, a race sailboat using exclusively renewable sources. The developed solution predicts the direct solar radiation on a horizontal surface. For that, a Nonlinear Autoregressive Exogenous (NARX) neural network is used. All the specific conditions of the sailboat operation are taken into account. The results show that the best prediction performance is obtained when the training phase of the neural network is performed periodically

WSN simulators evaluation: an approach focusing on energy awareness

The large number of Wireless Sensor Networks (WSN) simulators available nowadays, differ in their design, goals, and characteristics. Users who have to decide which simulator is the most appropriate for their particular requirements, are today lost, faced with a panoply of disparate and diverse simulators. Hence, it is obvious the need for establishing guidelines that support users in the tasks of selecting a simulator to suit their preferences and needs. In previous works, we proposed a generic and novel approach to evaluate networks simulators, considering a methodological process and a set of qualitative and quantitative criteria. In particularly, for WSN simulators, the criteria include relevant aspects for this kind of networks, such as energy consumption modelling and scalability capacity. The aims of this work are: (i) describe deeply the criteria related to WSN aspects; (ii) extend and update the state of the art of WSN simulators elaborated in our previous works to identify the most used and cited in scientific articles; and (iii) demonstrate the suitability of our novel methodological approach by evaluating and comparing the three most cited simulators, specially in terms of energy modelling and scalability capacities. Results show that our proposed approach provides researchers with an evaluation tool that can be used to describe and compare WSN simulators in order to select the most appropriate one for a given scenarioComment: 20 Page

Embedded Image Capture System for Liquid Monitoring in the Smart Chemical Industry

The work presented in this paper is carried out as a part of the design of a supervision system based on a visual wireless sensor network dedicated to the Smart Chemical Industry. Since the visual sensor nodes are battery powered, our objective is to reach a compromise between the energy consumption and the exploitability of the captured images. In this article, we are interested in how to highlight some important details of the image at the moment of its capture, a topic which has not yet been exhaustively covered in previous research works. As light is absorbed by materials through which it is passing, a correct image exploitability can be reached when applying the adequate light color. Thus, this paper studies the color light effects on the captured images. For that, one visual sensor node, based on Raspberry Pi and a camera, is designed to conduct experiments. In addition, a laboratory glass container including liquids is developed and used as an emulator of the real system.HYPERCOG H202

Image compression for WSN applied to the process supervision in Industry 4.0

Wireless Sensor Network (WSN) applications in the industrial sector are in permanent evolution due the emergence of the Industry 4.0 concept. Considering this context, Wireless Image Sensor Networks (WISN) appeared as a solution to supervise production processes. In this specific type of WSN, the size of the data to process and to transmit constitutes an important constraint that could cause network congestion and impact node lifetime. Thus, the goal of this paper is to study and evaluate a typical image compression algorithm as a solution to optimize the energy consumption and communication traffic in a WISN, dedicated to control a chemical industrial process.HYPERCOG H202

Linear electromagnetic energy harvester system embedded on a vehicle suspension: From modeling to performance analysis

Although linear electromagnetic energy harvester (LEH) is a promising technique for converting energy in a vehicle suspension, due to the large displacements, one of the main drawbacks of the solutions inside the vehicle is still their size and complexity. To address this issue, this paper focuses on the design and fabrication of a fully embedded LEH without any modification of the suspension initial structure. After a determination of the electrical, mechanical and electromechanical parameters using a Finite Element analysis, the dynamic efficiency is highlighted with a global Bond Graph model. This formalism is well adapted to simulate energy transfers inside multiphysic systems and to reduce the computational time, whereas the finite element model is not exploitable for a complete suspension simulation. In order to validate the Bond Graph simulation results, an embedded prototype has been built and tested in a laboratory environment. The embedded LEH system delivers around 10 W for a solicitation of linear velocity of 1 m/s which is sufficient to power a classical electronic circuit which is in good correlation with the measured ones and significant power has been obtained