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

Improving Low Power Listening (LPL) Mechanism to Save Energy Consumption in WSN

As stated in the literature, Low Power Listening (LPL) duty cycle is one of the most common energy conservation solution for WSN. By using channel check mechanism, the purpose of LPL solutions is to reduce the energy consumption of the listening phase. In this paper, we propose to study the performances and limitations of this kind of solutions. Therefore, we deploy a ContikiMAC LPL on both real and simulated WSN platform to demonstrate the impact of LPL on the energy consumptions of the node radio and microcontroller but also on the application Quality of Service. Based on the obtained results, shortcomings of LPL solutions are highlighted and potential improvements are discussed such as the use of multi-parameter dynamic duty cycle

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

Research experimental platforms to study microgrids issues

Microgrid (MG) concept is becoming increasingly mature. It allows integrating better distributed generation, and especially renewable energy sources, in the grid. However, many issues have still to be resolved before implementing this concept in the real power system extensively. This paper presents first a review of the main issues associated to microgrids dealt with in the scientific literature. The different issues are classified and some examples of carried out studies are given for each issue. Then, a short review of existing experimental microgrids is done. They are classified in small-size and real-size experimental MGs. After that, the EneR-GEA experimental MG or platform of ESTIA Engineering School is presented, describing its different components. Then, some carried out experiments are explained. To finish, the main planned projects at short and medium term related to this platform are given

An Approach for Modelling Wireless Sensor Networks: Focusing on the Design Concept and Energy Awareness

In the design stage, Wireless Sensor Network developers generally need simulation tools to save time and money. These simulators require accurate models to precisely describe the behaviors of network nodes. Nevertheless, although model complexity has grown 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 Network. Our modelling approach allows parameters that belong to different levels to interact and affect each other. This approach is used to predict the nodes energy consumption and to estimate the lifetime of the system. First, the results obtained from the implementation of our approach will be compared with those collected from a well-known simulator, Network Simulator version 2 using a set of basic scenarios. Then, the utility of our approach in the Wireless Sensor Network design process is highlighted using detailed scenarios that cover different types of interactions

Cross-level energy model for power-aware Wireless Sensor Networks design​

In many Wireless Sensor Network (WSN) applications, it is important to optimize the global energy efficiency in order to enhance node autonomy. Several factors impact the energy consumption in WSN, such as the purpose of the application, the network architecture, the hardware and software of the nodes. With all these factors in view, the definition of a model can provide a useful way to estimate this energy consumption. In this context, we propose a model that is energy-aware, phase-based and protocol-independent. Based on the energy consumption observation of typical WSN applications, our model introduces the pattern concept. It consists of different phases that take place periodically following a frequency Fp. The proposed model is first validated against a well-known simulator (NS2) using different scenarios and considering two wireless link protocols: 802.11a and 802.15.4. Our idea is to use this kind of simulator to monitor the energy consumed in WSN from different points of view. On one hand, the cross-level concept would be applied to minimize the computation resources needed to study the energy consumption of the entire system. On the other hand, at the same time, it offers the possibility to point out for details at different levels of the network. For example, with this simulator, both the consumed energy at the system level and the instantaneous power at the node level could be obtained and analyzed at the same time

A Cross-level model for power-aware Wireless Sensor Networks design

In many Wireless Sensor Network (WSN) applications, it is important to optimize the global energy efficiency to enhance both the node autonomy and the whole WSN lifetime. In this context, the achievement of a power-aware design is a complex task due to the impact over the WSN energy consumption of different parameters, which are inherent to application, network or node levels. Therefore, a cross-level energy model is a useful way to estimate this energy consumption, leading designers to take correct decisions at the earliest design stages. Thus, this paper describes the principles of a cross-level energy model, which tries to address some weakness of existing WSN simulators in terms of energy modelling