ABSTRACT. An effective and efficient drive should be capable of driving the Induction Motor (IM) on all four operation quadrants and running to full capacity in a well-controlled manner. In this paper, a Four Switch Three Phase Inverter (FSTPI) driving an IM using the Direct Torque Control (DTC) strategy is proposed. The theory and design of the drive system is outlined and then simulated with an IM model in the synchronous reference frame using Matlab/Simulink package. The drive is subjected to different system inputs and disturbances such as step changes in speed under different load conditions, abrupt loading at high speed and speed reversal. Also, the motor parameters that vary with motor operating conditions such as the stator resistance and moment of inertia are varied from the rated value to examine the motor speed dynamics. The results assure that the drive is valid with fast torque response, high stability and good dynamic performance.

ABSTRACT. Hybrid electric vehicles (HEVs) offer significant improvements on the car travelling autonomy, since they combine an internal combustion engine (ICE) with a pure electric traction. As HEVs become more complicated electromechanical systems, their good performance and response under the driver decisions, the road conditions and the requirement of optimal operation of the main traction devices, constitute a challenging engineering issue. The design of suitable controllers should satisfy all the aforementioned tasks but without any possibility for abnormal or unstable situations which may be dangerous or unsecure for the car passengers. In this paper, since the HEV system is clearly complex and nonlinear, a rigorous analysis is developed in which the nonlinear model of the complete system is considered. Suitable cascaded-mode controllers are applied on the aforementioned models and the whole system is analyzed in detail by using Lyapunov-based methods. The proposed design approach and analysis provide as simple as possible cascaded mode PI control schemes, with the critical controller gains effectively tuned in regions that guarantee asymptotic system stability. Evaluations via standard route conditions fully verify the theoretical results.

ABSTRACT. Interactions of modular multi-level converters (MMCs) compromising the system stability can be assessed by investigating the frequency behavior of the converter. The MMC Test Bench system replicates full-scale converters on a low-voltage level. It can emulate high-voltage direct current systems representing meshed offshore grids as well as the influence of wind farms connected to MMCs. Measuring the MMC Test Bench’s frequency behavior allows for assessing the frequency behavior of the applied control systems by avoiding simplifications of the electrical part of the MMC. This paper presents a setup for measuring the frequency-dependent impedance of the laboratory MMCs. The impedance is compared to small-scale as well as full-scale converter models. It is shown that the measured impedance can be scaled up for full-scale HVDC studies by means of derived correction factors. The results further demonstrate that simplified time-domain models can represent the MMC test bench but fail to represent the exact frequency behavior at low and high frequencies.

ABSTRACT. This paper proposes a chaotic unipolar sinus pulse width modulation (CUSPWM) algorithm for transformerless grid-tied single-phase photovoltaic (PV) inverter. The aim of the study is to reduce electromagnetic interferences (EMI) emitted by a PV inverter. First, a detailed description of theoretical developments is presented. Thereafter, the proposed CUSPWM is implemented and validated on a H5 PV inverter topology using a circuit type software. Moreover, a comparative study between the conventional unipolar SPWM and CUSPWM algorithms is carried out. According to the obtained results, the CUSPWM is advantageous over the standard SPWM control because it provides a significant reduction in the amplitude of both common-mode (CM) current and the CM voltage over a large frequency band.

ABSTRACT. PLC (Power Line Communications) present a wide range of advantages that make them very appropriate for Smart Grid applications, such as that there is no need to deploy additional communication infrastructure. However, they also involve a harsh communication medium, which suffers from frequency selectivity, impedance variation depending on the connected loads, or noise introduced by such connected loads. In this context, simulation tools are useful to evaluate the performance of this kind of networks under different conditions in an agile and cost-effective manner. Nevertheless, the typical complexity and learning curve of network simulators hinder their use, thus making it difficult to make the most out of them. In order to solve this problem, this paper presents two web applications that have been developed to ease the execution of simulations of NB-PLC (Narrowband) networks (based on PRIME - PoweRline Intelligent Metering Evolution) and of MV-BPL (Broadband Power Line over Medium Voltage) cells. These applications represent the first steps towards offering PLC simulations-as-a-Service, which could bring benefits to the research community, academic environments, and the industry.

ABSTRACT. This paper deals with a split capacitor three-phase four-wire inverter, able to deal with unbalanced ac currents and/or voltages. The considered topology can be used in many applications such as photovoltaic systems, chargers for electrical vehicles, active filters, and in general all the grid-connected applications. One parameter that must be considered in the converter design is the ac (output) current ripple, which should be determined and minimized in order to improve the system efficiency. In this paper, the evaluation of the ac current ripple for the three-phase split-capacitor inverter is developed with reference to both balanced and unbalanced output conditions. In particular, the peak-to-peak and the rms current ripple are analytically determined as a function of the modulation index, for each phase. Reference is made to sinusoidal PWM, being in general a simple and effective solution, but the unique possible modulation for the considered topology. Numerical simulations have been carried out in order to verify the analytical developments.

ABSTRACT. A wireless sensor network is made of a set of sensors, also called motes, in which each sensor node collects and transmits data to a special node called a receiver node or base station using radio waves. Sensor nodes have limited resources, such as battery power, processing, and wireless communication capabilities. In these networks, energy is consumed during data processing, listening, receiving data, transmitting data and relaying packets. Since the radio transceiver is considered to be the largest consumer of energy, it is essential to reduce the communication energy consumption in order to extend the life of the network. The radio transceiver should be turned off as much as possible. But when the transceiver is turned off, the node is unable to send or receive packets. Thus, the purpose of a duty cycle protocol is to frequently turn off the radio transceiver while providing enough meeting points for the nodes to communicate with each other. Many studies have been proposed on duty cycle protocols for various applications in wireless sensor networks. In this article, we used the Cooja Contiki simulator to assess and analyze the performance of three duty cycle protocols used by wireless sensor networks.

ABSTRACT. Due to environmental and economic reasons, the world is moving from bulk generation towards distributed generation. Microgrids (MGs) are a group of distributed energy resources, loads, and storage units that are controllable within clearly defined electrical boundaries. MGs have the potential to provide better power quality, reliability, voltage profile, and outage management. This paper aims at modeling and optimizing the size and operation of a MG. The MG must be able to exploit available resources such as solar, wind and other renewable energy sources. Technical and economic constraints are taken into consideration. A mixed integer linear programming model is used to find the optimal size of the different components then GAMS modeling language was used to find the optimal size of the different components and the optimal strategy to be followed. This enables exploring different scenarios. These scenarios are based on different parameters such as load and supply profiles. Solar irradiance and wind profiles have been used from the weather station at Birzeit University. Therefore, the data represents typical profiles in Palestine. Yet, the framework can be used to study building a MG in any location in the world.

ABSTRACT. As smart grids become more and more complex, the use of high level abstraction modelling becomes a crucial need to cope with the growing complexity of the control software. Defining commonly understandable software models is a challenging task due to many reasons such as the different disciplines involved to fulfil some functionalities, the various protocols to be used, the numerous constraints to be respected, etc. In this context, the current paper proposes a holistic meta-model that covers the requirements needed by a controlling software of microgrids. First, an overview of the existing modelling works is provided. Then, a formalization of a microgrid is defined. Finally, a discussion and evaluation of the proposed meta-model are provided.

ABSTRACT. Power plants have bad impacts on the environment. One of these impacts is Carbon Dioxide (CO2) emission resulted from power plants that depend on fossil fuel, oil and natural gas. Renewable energy is considered as an important solution for this problem since it is classified as clean and environmentally friendly source of energy and helps reducing the dependency on conventional power plants. High renewable energy penetration into power systems is a big challenge that can be solved by deploying the concept of smart Micro-Grids. This paper presents a study on how much reduction of CO2 emission can be resulted from deploying smart micro-grid concept on a university campus, German Jordanian University (GJU) campus was taken as a pilot. The micro-grid is meant to operate according to an optimum resource scheduling framework that guarantee a minimum operational cost while achieving high local power availability.

ABSTRACT. This paper describes the novel methodology for load management control system with continuous power power supply feature in Pakistan. Smart meter and smart grids are the crucial components of this proposed power management system for diminishing the possibility of load shedding. Also, this methodology makes it possible to utilize the available energy resources more efficiently using internet of things to overcome the higher energy demands. The advanced metering infrastructure uses the power demand and supply information available from the communication network in managing the demand and supply, real time pricing problems and also control over energy theft. Moreover, mathematical analysis supports the efficacy of proposed methodology.

ABSTRACT. In modern distribution grids, accessing the growing amount of data from various sources, running complex algorithms on-demand, and controlling sparse actuators represent important requirements. These can be achieved with on-demand scalability to support fluctuating workloads. A possibility to provide on-demand scalability is cloud computing. This paper presents a cloud-based platform that analyzes power distribution grids data and deploys a service restoration application for the re-energization of loads after electrical faults. The implementation of this study is powered by FIWARE, which is based on open-source and customizable building blocks of future internet applications and services. The feasibility of the service restoration application is evaluated through the analysis of its network latency and computation time in different test cases.

ABSTRACT. Demand Side Management, DSM, is a program supported by the smart-grid which aims at matching the energy consumption and production. Several techniques for demand-side management have been proposed including load-shedding, time of use pricing, real-time pricing, and critical peak pricing. In this work, we propose a distributed load-shedding algorithm using the multi-agent system. The agents in residential areas collaborate to reduce the energy demands using various forecasting techniques. The computational distributed framework is provided via fog computing to reduce power consumption, costs, and latency when designed using LoRaWAN protocol.

ABSTRACT. This paper proposes an enhanced control of DC wind systems connected to imbalanced bipolar DC microgrid. Two wind systems are considered each one is connected to a different bipolar DC microgrid terminal and exposed to dissimilar wind speed profile. The studied DC wind systems are based on doubly fed induction generator. Each one includes two voltage source converters, a rotor side converter controlled to ensure Maximum Power Point Tracking via a predictive algorithm, and a stator side converter controlled to ensure equilibrate three-phase voltage in the stator side, also via a predictive algorithm. Simulations are carried out via PSIM software to validate the effectiveness of the proposed control on reducing the effect of the BDCMG imbalance on DC wind turbine efficiency.

ABSTRACT. In the current work, dye-sensitization approach was used to optimize the compact layer/perovskite interface in perovskite solar cells (PSCs). Our attention is focused on designing a Schiff base complex derived from ninhydrin and glycine ligand (NG) with Co (II) metal (Co-NG) as sensitizer for TiO2 and a ZnO electron transport layers, prepared by sol gel method. The two electrodes and complex are characterized by X-ray diffraction and UV-vis spectroscopy. Furthermore, a Density Functional Theory (DFT) calculation is performed to achieve supplemental insights about the optoelectronic properties of Co-NG complex. As a result, the dye exhibits good optical behavior with two maxima around 415 nm and 604 nm and high molar extinction coefficient equal to 27.5 × 103 M−1 cm−1. Moreover, to predict the possibility of introducing the modified electron transporting layers (ETLs) in PSC devices, the optical properties is tested and strong interactions between the dye and the ETLs are founded. Accordingly, the numerical simulation of PSC based on TiO2/Co-NG and ZnO/Co-NG layers shows a good efficiency enhancement equal to 18.94 % and 16.32 %, respectively, compared to the reference solar cells.

ABSTRACT. In this work, ultraflexible monocrystalline silicon solar cells are developed using a corrugation technique. The corrugation method consists of producing alternating trenches following different patterns. By applying this technique on large scale solar cells with rear contacts technology, ultraflexibility is enabled with unimportant deterioration in the electrical behavior. The different patterns allow for different characteristics of the solar cell with regard to flexing capability output power and weight. Finally, cycling tests confirm the mechanical robustness of the encapsulated flexible solar cells using a transparent and ecofriendly polymer.

ABSTRACT. The present study aims to find the best location for installing wave energy converters (WEC) in the NEOM area, located in the Red Sea northern region, and to determine the most suitable converter system for harvesting wave energy using available data provided by KAUST. The Red Sea region represents a challenge for wave modulization and analysis due to its two distinct and opposing wave structures induced by reverse winds that converge at its middle. By incorporating wind and wave data series from 1985 to 2015 in the Advanced Research Weather and Forecasting model and WAVEWATCH III. In the present study, the highest peak period found in the selected area is 4 seconds based on the wave hindcast generated on a 1-km resolution grid, and the highest wave found was 0.79 m. A total of 8 points were selected and analyzed to test the potential of wave energy at NEOM coastlines along the Gulf of Aqaba and NEOM Bay. Based on the results, the Gulf of Aqaba, with a mean wave power of 1.98 kW/m at P#2 is a good candidate for a WEC system. Possible installation of wave energy converters in the selected areas is discussed in this thesis, including farms of point absorbers with the integration of wave and solar sources (DEIM). Based on preliminary information regarding the NEOM region, potential environmental and social challenges were identified in this study for the viability of wave energy exploitation.

ABSTRACT. Large tidal current devices are experiencing technological convergence into two or three-bladed horizontal-axis configuration. Most devices use a gear-coupled drive-train, a permanent magnet generator and power electronic converters. This work presents a wire-to-water comprehensive dynamic model of a generic tidal current device. The model is assessed under varying water flows, device settings and diverse operational conditions that are unique to tidal applications. The detailed model can be further modified to fit specific user needs, including, device design, control settings, resource assessment, or power system studies.

ABSTRACT. Nearly one million Rohingya people now live in Cox's Bazar, Bangladesh, the world's biggest refugee camp. Burning firewood by these people for cooking purposes would intensify the deforestation that will eventually seriously damage the Cox's Bazar ecosystem. Since this part of Bangladesh is flourishing with ample solar radiation, the use of a parabolic solar cooker can be a good alternative to cooking. This paper demonstrates the development of a solar parabolic cooker using low-cost materials to be used in the rehabilitation program for Rohingya. The cooker has an aperture diameter of 62 cm and a focal length of 44 cm. Mylar tape is used as a reflective material that helps to concentrate solar irradiance at the focal point of the incident. The black cast aluminum vessel which serves as the cooking pot absorbs the concentrated heat. Experimental results show that 500 gm of rice can be cooked within 50-55 minutes by the developed solar parabolic cooker. Besides the highest water temperature 373.05 K is achieved by this cooker. Moreover, this parabolic solar cooker can cook an omelet within 5-7 minutes.  In addition, the parabolic solar cooker is tested at different weather conditions and the maximum cooking temperature of 390.95 K is achieved.

ABSTRACT. A surge in harmonics and distortion in the South Africa’s electric power system has come to the fore in the early phases of integrating renewable energy resources to the national electric grid. Having said that, in this day and age a considerable number of harmonic producing apparatus are present. These includes semiconductor devices such as transistors, IGBTs, MOSFETS, diodes and electrical apparatus suchlike rectifiers, variable-speed drives, inverters and electric motors. On the basis of their beneficial effects in efficacy and controllability, harmonic producing apparatus are presumed looking ahead to the realization of the 2030 Integrated Resource Plan (IRP 2030) to increase further. The IRP 2030 is aimed at increasing the total renewable energy generation capacity contribution to about 24.7%. Further to this is a considerable increase in the amount of harmonics in the electric power network. The mushroomed harmonics and distortion may drive inflated winding stray loss and thereby peculiar temperature rise phenomena. Undue losses have classically been presumed to be varying in direct proportion with the harmonics order and load current. In this paper, the transformer losses that occur when facilitating solar PV farm environment are investigated based on seasonal basis. The study in particular draw attention to the injection of harmonics and distortion using the IEEE Std. C57.110-2018 recommended practice. In the worst-case scenarios for summer and winter the harmonic current measurements were taken to evaluate the guaranteed services losses. The hourly mean harmonic current profile for summer and winter solar irradiation of a solar PV farm are presented to investigate their effects on the operation of the transformer during service. The findings of the investigation is projected to be used as a foundation for the IPP’s and manufacturers for operating and designing transformers serving large-scale solar PV farms within acceptable maximum rating in taking into account the availability of solar irradiation on seasonal basis and robust parametric design at tender stage respectively.

ABSTRACT. South Africa has established one of the most reputable renewable energy programmes in the world. The latter presents a new energy mix in the country, and as a consequence it is important to acknowledge the operational characteristics of each power utility. Subsequently, it is crucial then to evaluate the service lifetime cost of each kilowatt as far as the step-up transformers are concerned as it might be different. The Total Ownership Cost is a financial evaluation method meant to render transformer buyers the purchasing and after purchase costs of their transformer expenditure. The method applied in centralized electrical utilities does not quite satisfy the intermittent generation profile experienced by transformers within solar power plants. This paper presents an in-depth loss evaluation procedure to calculate the total ownership cost of transformers expected for service within utility-scale solar photovoltaic plants. These transformers could be owned by Independent Power Producers. More particularly, the proposed method recognizes the intermittent generation profile of the solar plant.

ABSTRACT. With the increased adoption of smart grids in recent years, industrial consumers have to devise effective ways of promoting their interaction with utility companies. Industries can leverage on the capabilities of a smart grid to design effective energy management schemes to better position themselves in their various sectors of operation. This paper incorporates the aspects of a smart grid in designing an energy management system (EMS) where demand side management (DSM) is utilized to enable industrial users control their energy usage and minimize costs. A load scheduling algorithm is developed based on the predicted electricity prices to ensure energy cost savings. The non-priority loads are scheduled to leverage on low electricity prices during off peak times. Long Short Term Memory (LSTM) which is a Recurrent Neural Network (RNN) technique is used in designing the prediction model. The effectiveness of the designed energy management strategy is tested using an IEEE 30 bus system. A suitable operation schedule with committed units for each hour is given for one sample day.

ABSTRACT. Microgrid systems have received much attention as they can make a way for more efficient power flows in the modern power systems. This paper presents a hybrid AC/DC microgrid to reduce the processes of multiple conversions in an individual AC or DC microgrid. In this paper, a new method of the supervisory controller is proposed to autonomously control and monitor for an islanded microgrid and to maintaining more stable energy flows with maximum utilization of renewable resources. The supervisory controller enables the microgrid system to operate in different modes of operation by the coordination control algorithms in the different components for smoothly transfer of power between AC and DC networks. With the energy management option of the supervisory controller, this supervisor also provides an efficient load scheduling method to meet varying power supply needs and manage the sources and allow the microgrid to make a good operation and decisions. Therefore, in this paper, an islanded AC/DC microgrid has been modeled and simulated to identify the relevant technical issues involved in the operation of a microgrid system based on renewable power generation units using the Simulink -MATLAB, and a new method of an energy management system is proposed or monitoring the islanded microgrid.

ABSTRACT. The objective of this paper is to present a three layered microservice based approach to designing a Software as a Service (SaaS) based building energy management system (BEMS). The "Core layer" is comprised of microservices performing core functionalities of the system, the "API layer" serves as a gateway between the core system and front-end services. Finally the "Service layer" provides the SaaS functionalities and applications experienced by the end-user. This paper presents a microservice based energy management system that can be effectively used by an end user to monitor and control electrical equipment and can be integrated into a large power system network. The proposed architecture has been used to develop a cloud based web interface and an iOS/android application of a building energy management system.

ABSTRACT. The coordinated and efficient operation of Solar PV system combined with battery storage systems makes a standalone DC Microgrid stable and reliable. The accurate power sharing between the distributed renewable energy sources of a DC Microgrid according to the available source and load demand is managed through droop control algorithm and droop resistance adaptable to the variations in the sources (Uncertainties in Solar Power). This paper presents an adaptive droop control algorithm developed based on the existing source converted as the reference current for operating the converters to meet the demand. The changes in the output voltage of each converter is controlled and is maintained constant throughout the operation of DC microgrid and makes it stable. The proposed control algorithm is implemented to the system individually to make it a communication less control. The adaptive droop control algorithm relies on the local measurement data from each converter like, output voltage, current, rated load current and DC Bus voltage. The control strategy is applied to a simple DC microgrid representing a local community grid with solar PV as the source and battery as the support system on standalone mode of operation developed using MATLAB/SIMULINK and is validated for three different power sharing scenarios.

ABSTRACT. A solid-state transformer-based smart transformer (ST) can operate in meshed and hybrid grids, which can increase the hosting capacity of renewables and meanwhile reduce the reinforcements in electric grids. In order to adapt the new paradigm, the system performances of the ST-based meshed and hybrid grids are studied and then an effective energy management system (EMS), which is based on a distributed control architecture, is presented to control the meshed and hybrid grids operating in an intelligent and coordinated way.

ABSTRACT. The complexity and the decentralization of Micro-Grids have led to management and diagnosis issues because of using distributed power sources, especially the renewable energy sources. Wireless Sensor Networks can substitute part of the communication infrastructure of the Micro-Grid, it deploys between its elements in order to ensure data flow in real time. It allows energy management applications to have more interesting cost and efficiency. The present work discusses the Wireless Sensor Networks usage dedicated to energy management and default diagnosis in Micro-Grids.

ABSTRACT. The opensource Modelica package for a specific type of phase change material (PCM) ventilation unit is developed. The model is built of components from Modelica Standard Library (MSL) and IBPSA library as a part of Termonet library aiming at opensource models for household owners and utility companies to help to integrate sustainable technologies into district energy networks. The PCM heat exchanger model instantiating IBPSA library fluid components are compared to MSL PCM implementation with no fluid components and the Matlab-inspired textual Modelica model. MSL-based and textual models are shown to produce identical results, whereas account of fluid properties leads only to a slight deviation. This can motivate the use of the MSL and IBPSA-based models as a control and emulator models in Model Predictive Control. Essential fluid models from IBPSA library can be compiled and simulated using OpenModelica with minimal tuning, which shows the potential of the IBPSA library as a fully opensource building performance simulation tool.

ABSTRACT. The evolution of world’s primary energy supply over the last 2 decades is presented, along with the outlooks and scenarios for the upcoming ones. The COVID-19 pandemic had a major impact on the energy demand and supply patterns in 2020, as well as on the energy-related greenhouse gas emissions. This change in energy and emissions trajectories provides the opportunity to fast-track policies and technologies to enable a cleaner energy transition, and target net-zero emissions by the middle of the century. The energy transition requires a number of decarbonization wedges to be fast-tracked, such as CO2 capture and storage and Hydrogen.

The implications for the Energy outlooks of the North African region and in particular Tunisia are then discussed.

ABSTRACT. RTE is the French Transmission System Operator. It owns, develops, maintains and operates the power grid serving load of 460 TWh, with 100.000 km of lines and cables, 2 700 substations ranging from 63 kV, 90 kV, 225 kV and 400 kV. It plays a major role in order to enable a successful energy transition, with more intermittence, more renewables, smart or micro grids. It has to make the most existing assets and to increase the sustainable development concept in the design of the new components to be installed on its grid. R&D and innovation, new technology, telecommunications and computation are part of the package to reach this target. This presentation falls into two classes. In first, we present new developments made in order to make the most of the existing assets, and to increase the use of the grid by boosting its potential power flow, keeping in mind the necessity of system security at all times respecting N-1 criteria. For this, part of the answer comes from the idea of getting near the real maximum circuit ampacity by monitoring weather conditions (Dynamic Line Rating, or DLR) for Overhead Lines (OHL) as well as conductor temperature for underground power cables, in this case using optical fibers. In this last case, a design of cable with embedded optical fibers is presented. Likewise, the digital underground link will permit to limit the number of cable outages. Another way to increase power flow is to use adaptive and flexible electronics devices (Smartmodules). A last example in this category is the use of battery at subtransmission level in order to compensate for potential local congestion, in particular due to local renewable generation. In the second we illustrate the company’s strategic objective to be at the forefront of eco-design. The eco-design approach is fundamental, and goes across all the company’s activities. Eco-design aims at reducing the company’s global footprint. The development of new technology can help to make the most of existing assets, and thus limit the unnecessary development of new infrastructure. It contributes globally to energy savings. In this paper, we present a particular topic concerning SF6 emission. The development and installation of an SF6-free substation is detailed. This opens the way for a strong decrease in the usage of a gas listed amongst the worst in terms of Global Warming Potential (GWP).

ABSTRACT. The multiplication of new energy devices (electric vehicles, energy storage, active loads, etc.) connected to the distribution network along with the ever proliferation of renewable energy intermittent sources constitute a network instability threat; mainly because of the reactive power exchange between those active devices. Moreover, uncontrolled circulating harmonics between time and frequency varying reactive impedances devices causing therefore important voltage distortions, and power quality disturbances to the distribution network.

For the last several years, researchers have been working on developing remedial power electronics devices and control strategies to reduce those impacts. New topologies of multilevel type of power electronics converters, which can help attenuate the problem have been introduced and the lots of research effort in this direction is taking place around the world.

The presentation will focus on latest development of new technologies while highlighting the challenges facing the growth of interconnecting renewable sources through power electronics converters to the grid as well as the latest development on reduced filters power electronics devices.

ABSTRACT. To face ecological constraints and growing energy demand we should resort to renewable energy sources. Using solar energy as input source for Stirling engine is an interesting alternative. The objective of this paper is the study and the simulation of a small-scale solar Stirling engine generator. The simulation deals with modeling mechanical as well as electrical parts of the system. All the thermal, thermodynamic and mechanical aspects are considered in the engine part and the solar collector. The electrical part composed of a synchronous generator and ac/dc convertor are simulated using Matlab/Simulink blocks.

ABSTRACT. The adoption of solar photovoltaic energy in the residential sector is growing rapidly. Every year millions of new systems are installed. Most of these systems are not equipped with a monitoring system. We propose to develop an efficient and open hardware software monitoring system for photovoltaic installations. The proposed energy monitoring system is designed to be low cost, simple to use, robust (handles internet outage) and data must be easily accessible via different mobile and web platforms.

ABSTRACT. The intermittent nature of solar energy poses a huge challenge to the optimization and planning of future smart grids. In order to reduce intermittency, it is very important to accurately predict photovoltaic (PV) power generation.

ABSTRACT. The study of engineering solutions presented by the authors in the area of energy-saving and energy-efficient technologies for transport aiming at searching for the concrete decisions and the ways of their implementation has been made in the article. One of the most possible and obvious solutions is to combine all the proposed solutions into a single energy-efficient system for urban transport. Analytical methods of research were used in developments and investigation of the methods and devices for converting energy of the sun into the electric energy. An ultra-capacitor electro-bus with superfast charging has been offered as a kind of urban transport. This electro-bus is capable of transporting people without wasting time for recharge of storage batteries. An engineering solution on multifunctional panels of pavement has been presented. A way to make road markings and control transport movement automatically has been suggested. A device for generating electric energy that can be used as an alternative source of electric energy in places with dense people or transport traffic has been proposed. The presented engineering solutions are energy-saving and energy-efficient. Their implementation and use in transport will make possible to reduce both consumption of energy and dependence on the centralized sources of power supply. Combining all the above proposed energy-efficient technologies, it is possible to create a project of a single energy-efficient system for urban transport.

ABSTRACT. Saudi Arabia promotes the distribution of renewable energy resource such as PV application to help achieve its 27 GW renewable energy targets in 2024. In this paper, we aimed to perform a techno-economic analysis of 30 KW grid-connected rooftop solar PV system with batteries to provide power supply for the same load but based on a number of variables including location and the availability of solar irradiance. We have chosen two different regions in Saudi Arabia which are Riyadh (in the central region) and Tabuk (in the northwest). The paper outlines analysis of the grid-connected solar PV system by computational technique. Various parameters were calculated for both regions and comparison have been made for selecting and optimizing the most ideal location. The overall efficiency of the two systems including capacity factor, performance ratio, capacity factor, levelized cost, and net savings of the system were discussed. The paper aims to study the economic feasibility of constructing and connecting a PV solar system with batteries at customer building from the end user’s perspective. The study give a clear insight about the attractiveness of the investment for given end users.

ABSTRACT. For a distributed system like the power grid, the requirements on fast and reliable communications are increasing due to build out of intermittent renewable energy sources, reduced inertia in the power production and high power loads. Mobile networks have been promoted as a prime candidate for the communication in smart grids since the introduction of 4G. However, most deployments still rely on other network technologies. In this paper we review the challenges of using the existing 4G mobile networks and notice that the average performance is typically at an acceptable level, but the latencies of higher reliability percentiles are very high. This makes control applications with high reliability requirements problematic over unmanaged networks, such as the Internet or public mobile networks. Mobile networks are complex systems with large number of mechanisms that may be used to improve the reliability and latency of all the steps of the end-to-end communication path. In critical events, such as power outage, a storm of alarms from different sensors will be triggered. In this paper we consider how short response times can be provided to smart grid devices also at such events. This is a step in evaluating the best way of configuring mobile networks for smart grid communication as we move from 4G to 5G mobile networks.

ABSTRACT. The accurate and reliable measurement of energy consumed by residential, industrial, and commercial properties is crucial in billing, controlling, and the monitoring of the usage of energy by both the utility provider and the consumer. The conventional metering methods used for the measurement of energy are prone to various forms of irregularities such as time consuming, inconvenience, energy theft, loss of revenue due to fraud, capturing of incorrect meter readings due to human error and so on. Thus, the proposed study will focus on the design and development of Automated Meter Reading system (AMR) using Global System for Mobile (GSM) technology and load control through Short Message Service (SMS) for domestic purposes. This system offers a solution to the anomalies posed by the conventional metering procedure as it allows the utility supplier to have access to surveillance capabilities, total control over client load and remote power interruption. Furthermore, the designed system will provide some modifications like the additional features such as the security circuits, power reconnect and using the GSM network for the purpose of centralization of billing system. The system hardware will be modelled and simulated in MATLAB. The design components will constitute of a microcontroller, GSM modem, LCD, and a latching relay. A microcontroller unit will be connected to a digital energy meter that will take readings from the energy meter and display the same data on LCD. The readings will be sent also to the control room by SMS via GSM modem being fed from the microcontroller. The GSM receives commands from the cellphone to control the usage of electricity by the users. In cases pertaining to unpaid bills and penalties on late payments, the users will get notification messages. The proposed design system will add meter tempering detection feature to detect and handle power theft issues.

ABSTRACT. Energy efficiency (EE) is an important objectivefor machine-to-machine (M2M) communication systems in wire-less network, due to the limited capacity of batteries in userequipments (UEs). In addition, M2M devices at the cell edgeinevitably suffer from the co-channel interference (CCI). Thispaper addresses the mobility control (MC) for M2M in LongTerm Evolution (LTE) systems with cooperative relaying for CCI avoidance and EE improvement. Considering the signal-to-interference ratio (SINR) gain and lifetime, the proposedscheme allows M2M devices in the cell edge to achieve high EE. Simulations results show that the MC scheme under cooperativerelaying outperforms the non cooperative scheme.

ABSTRACT. The extensive increase of photovoltaic (PV) system installations is related to the drop of the renewable energy equipment cost. A big number of these PV generation systems are installed in remote areas as well as in residential ones. Therefore, complex wireless data acquisition systems are required for the monitoring of these installations. In this context, the present paper deals with a low cost designed measurement system based on an STM32 microcontroller. This system aims to measure the PV module current and voltage and to compute the resulting produced power and energy. The collected data are stored into a micro SD card and are sent to the user via Bluetooth. This measurement system affords real-time monitoring of the installation that will facilitate its maintenance, fault detection and will provide a record of all the data at fixed intervals.

ABSTRACT. The optimal performance of power system operation is dependent on many factors, and one of which is the reliability of the station communication network required for real time monitoring and control operation of the station. Real time operating data are vital to the advancement of substation communication network design and operators are often eager to know the behavior of the substation communication network to enable the operators perform real time monitoring and control of the grid network through the communication network. These network historical data are also required for predicting future performance of the network. This paper has demonstrated successful use of communication network collected data to determine the reliability and performance of an IEC 61850 substation communication network. The key findings of our study are that the derived network has a high reliability and will be able to perform its required protection, monitoring and control functions, increased data rate reduces network latency and network redundancy scheme increases the network reliability. Based on the derived network reliability, the increased data rate, reduced network latency and network redundancy scheme increases the network reliability averagely by 3.8% over fifteen years period.

ABSTRACT. As a widely used traditional non-isolated DC-DC converters, the Boost converter has large switching current stresses and voltage stresses, and its voltage gain is limited by the circuit parasitic parameters. Interleaved technique is usually used to improve the power of the converter. However, when the parasitic parameters of each phase are unbalanced, the inductor currents of the converter will be unequal. Thus, the traditional interleaved DC-DC converters usually cannot operate under open loop control, because the converter needs a control method to balance the inductor currents. In order to improve the voltage boost capacity and increase power of the converter, a high-gain four-phase DC–DC converter is proposed. Voltage gain of the converter is about four times as traditional Boost converter and the converter has low switching voltage stresses and current stresses. What’s more, the converter has current and voltage self-average feature. Therefore, the proposed converter can operate under open loop control. The current and voltage self-average abilities make the closed loop design of the converter only need to sample the total inductor current and output voltage, which simplifies the design of the closed loop system. Switching strategy, working mode, steady state analysis, simulation and experimental verification are analyzed in more detail.

ABSTRACT. The ongoing decommissioning of conventional power plants decreases the installed reactive power reserves for voltage control in transmission grids. Hence, an efficient planning of compensation devices substituting this lack of reactive power is required. Grid operators must allocate these devices for steady-state voltage control and for dynamic voltage control ensuring voltage stability. A separate determination of this static and dynamic VAR demand, however, fails to exploid synergies and disregards that VAR compensation in steady-state reduces the reserves for dynamic compensation. This paper proposes a coupled determination of the system static and system dynamic VAR demand. An optimisation method applying mixed-integer programming identifies an efficient allocation and portfolio consisting of different compensation technologies. It includes constraints for voltages during steady-state and contingencies as well as for long-term voltage stability. Results emphasise that the method identifies an efficient portfolio for various operation and fault scenarios, while providing the required voltage stability margin.

ABSTRACT. In this paper, a modified predictive current control (MMPC) strategy with replacing zero vectors by two active vectors V1 and V2 for a voltage source inverter is proposed, with the purpose of obtaining a better harmonic performance and a reduction of the common mode voltage. The efficiency of the proposed control strategy is evaluated using numerical simulation. Obtained results show a decreasing THD as well as mitigation of CMV. They are compared with the ones obtained by conventional model predictive control and the MPC with avoiding the zero vectors.

ABSTRACT. Capacitor voltage transformers are widely used as voltage transducers for metering and protection applications in high voltage transmission networks. The frequency response of the voltage transformation ratio of a capacitive voltage transformer, however, exhibits resonant characteristics, which limits the usefulness of these transducers for wideband application such as the measurement of harmonic voltage components. The measurement errors induced by this non-ideal frequency response can, in principle, be corrected using the measured or estimated transformation ratio frequency response of the transformer. This paper explores the use of a pseudo-random impulse sequence perturbation signal to measure the frequency responses of a capacitive voltage transformer and determine the associated equivalent circuit parameters. In the proposed test topology, the perturbation signal is applied to the secondary terminals of the test device, and the model parameters are estimated from the frequency response of the secondary input impedance. Estimated parameter values, and measured and simulated frequency responses, are presented for the secondary input impedance, secondary to primary transformation ratio, and transconductance ratio of a 400 kV/110 V capacitive voltage transformer. It is shown that frequency responses simulated with the estimated parameters correlate closely with the measured responses.

ABSTRACT. Extreme environmental conditions can alter the surface properties of insulator surfaces causing a temporary or permanent loss of hydrophobicity. Biological contamination such as algae, fungi, and lichen decrease the flashover performance of the insulator and poses a potential threat to the safe operation of the power systems. This biological contamination poses a major challenge in the operation of electrical power systems, which decreases the flashover performance of the insulator, which can result in the complete failure. The bio-films also has the ability of retaining water on the insulator surface, which results in increased leakage current levels under wet conditions. These leakage currents, which are caused by the biological contaminating, are also considered as one of the most of serious problems of insulators in service, which causes the formation of dry band arcing which could results in a flashover that can cause power outage. This paper present among others climate parameters, humidity, pollution, high temperature, ultraviolet exposition, sunlight and atmospheric pressure and biological degradation, which causes microorganisms in the air

ABSTRACT. An important application in the Smart Grid area is the large-scale application of measuring systems in Distribution Networks (DNs) with the Micro Phasor Measurement Unit (μPMU). The majority of traditional μPMUs and Phasor Measurement Units (PMUs) use GPS as time synchronization signals. However, this time synchronization system limits the installation of μPMUs outdoor and they will remain expensive. In this context, IEEE 1588 comes as an effective way to enhance performance in time synchronization, it can allow microsecond accuracy and is designed for wired and wireless networks. Moreover, the wireless Precision Time Protocol (PTP) reduces the convergence time and the number of packets required for synchronization without compromising on the synchronization accuracy. On the other hand, the embedded systems make the Micro Phasor Measurement Unit (PMU) becomes possible since the volume of PMU will be small and easy to be installed. This paper proposes a novel PMU synchronized by a wireless IEEE 1588 Precision Time Protocol (WPTP) which enables precise synchronization of clocks via packet networks.

ABSTRACT. This paper performs a value network analysis on the electricity market. The study introduces current value network setting in the electricity market. Critical roles and activities and their setting in the value network are introduced. Based on four future scenarios built by business model matrix analysis, changes in the value network, new roles, and emerging/evolving activities are discussed. The outcome of the study yields to the introduction of two new emerging roles (brokers and representatives) in the future peer-to-peer electricity markets. These roles are discussed from legal, data protection and grid structure perspectives.

ABSTRACT. Growing environmental threats have brought to the fore the need to transition into clean and sustainable economies. Countless ground-breaking technological developments have been made in pursuit of discovering and integrating better energy sources such as electric vehicles for smart grids. This paper aims to study a proposed simulation environment representing a micro-grid containing a fleet of electric vehicles with a limited vehicle-to-grid application. In fact, the discharging mode is only applied in the case of peak demand with a very high response time. The building blocks of this micro-grid are outlined and modeled and a simulation of their operations is presented. The paper delves into the management strategies used to regulate the power in this simulation and investigates further the charging and discharging scenarios.

ABSTRACT. Lack of efficient acquisition of power consumption data in Electrical Secondary Distribution Network (ESDN) is one of the major challenges facing the Tanzania Electric Supply Company and other utilities in developing countries. Despite its huge importance in the planning, forecasting and general management of power distribution, data acquisition is currently done using manual and estimation methods. The readily available solution is smart meter which faces affordability issues, the study proposes affordable multiuser acquisition system formed by sensing nodes equipped with Zigbee modules for routing data from acquisition points to a gateway where they can be routed in bulk to utility’s center station for storage, analytics and further processing. The system was developed and then deployed, the analysis of the performance and the cost of the system approves the feasibility of the acquisition system both in terms of cost reduction and performance.

ABSTRACT. The fault current in a PV-integrated microgrid (PV-MG) has a relatively low value and an unpredictable phase angle, making current-measurement based fault detection techniques highly unreliable. This paper investigates the ability of conventional distance protection to detect and allocate balanced (LLL-G) faults on MG feeders emanating a PV inverter (PVI). Different PVI grid-support settings are investigated. PSCAD simulations show that conventional distance protection can reliably detect solid LLL-G faults on feeders emanating from PVIs. In the case of non-solid faults, however, conventional distance relays fail due to the unpredictable phase angle between the PVI fault current and the grid fault current infeed. Subsequently, the study proposes a novel high-frequency current injection (HFCI) distance protection scheme capable of accurately detecting faults regardless of fault resistance. PSCAD simulations prove the speed and reliability of the proposed HFCI distance scheme in both grid-connected and islanded modes of operation for both solid and non-solid faults.

ABSTRACT. this paper addresses, for the first time, the openswitch fault detection in a single-phase five-level packed U-cell inverter (PUC5). The proposed detection and isolation method is based on the analysis of only the output voltage signature. This latter reveals a specific distortion caused by the faulty switch.Its identification is achieved upon the location of the distortion within the fundamental period of the output voltage. Numerical simulations and experimental tests confirm the effectiveness of the proposed method in detecting open-switch faults in the PUC5 inverter.

ABSTRACT. The rapid expansion of wind farms has drawn attention to operations and maintenance issues. Condition monitoring solutions have been developed to detect and diagnose abnormalities of various wind turbine subsystems with the goal of reducing operations and maintenance costs. This paper explores fault data provided by the supervisory control and data acquisition system and offers fault prediction at three levels: (1) fault and no-fault prediction; (2) fault category (severity); and (3) the specific fault prediction. For each level, the emerging faults are predicted 5–60 min before they occur. Various data-mining algorithms have been applied to develop models predicting possible faults. Computational results validating the models are provided. The research limitations are discussed.

ABSTRACT. Higher voltage and current harmonics can produce negative impact on power system grid, so it is necessary to reduce their impact to the level of proposed norms and standards. To achieve this, it is necessary to identify the major sources of the higher harmonics. Often, significant changes in the power system can occur over time, due to the installation of new equipment on the distribution side or due to the changes in the load at end user side. In the case where end users create harmonic distortion in a point of common coupling, the distribution system operator shall provide measurements and determine the cause/source of the distortion. Except for the grid operators (transmission and distribution), the system for determining the propagation direction of higher harmonics can be also important for “internal” power grids of larger industrial users. There are several methods through which the propagation of higher harmonics in the power grid can be determined. The methods differ according to the input data and the number of measurement points required for their calculation. The basic division is made by number of measurement points - multi-point and single-point methods. There is no generally accepted method in the current literature or any general guidance/ standard recommending one method. Each method requires different input parameters, and not all methods are equally applicable in practice. The aim of the paper is to examine the accuracy and applicability of proposed method for determining the direction of higher harmonics based on single point measurements, and to explore and prove the possibilities of implementing them on the existing measurement infrastructure. Based on the data (direction of power harmonics) collected from several measuring instruments in a part of the power system, the system operator can locate the cause of harmonic distortion in his power system.

ABSTRACT. Road transport has been identified as one of the top contributors of greenhouse gas (GHG) emissions from the energy sector in Rwanda [1]. The Ministry of Environment in its Third National Communication Report to the United Nations Framework Convention on Climate Change proposed different mitigation solutions including the introduction of electric vehicles (EVs) and fuel efficiency systems. The main motivation is to replace diesel-fuelled cars with EVs starting from 2020 in Rwanda [1]. EVs are projected to replace 150,000 passenger cars by 2050 and according to the projection, these EVs will require an average of 30 kWh per 100 km [1]. In this paper, a feasibility study of introducing EVs in Rwanda’s transport system is investigated. Simulation results show that 1.5% of the registered private vehicles, 10% of the registered buses and 10% of the registered taxis charging at 10 kW can be replaced with EVs with a minimal impact on voltage profiles. This study found that 1%, 8% and 8% of the registered private vehicles, buses and taxis can be supported with 20 kW chargers. However, an addition of two large-scale distributed generation (DG) units is required with 20 kW chargers in the network.

ABSTRACT. Power systems are experiencing an increased uptake of distributed energy resources (DERs) such as photovoltaic (PV), wind power, battery energy storage systems (BESS) and electric vehicles (EVs). While several benefits can be derived from DER penetration, several technical issues may result. The most reported issues include voltage-rise, voltage-drop, unbalance, and the thermal loading of conductors and transformers. For these issues, the severity depends on the conditions and level of penetration. As a result, current research is focused on deriving limits for penetration for regulation on existing networks. For new electrification systems, the uptake of DERs demands new planning principles such that the sizing and selection of network equipment, such as feeder cables and transformers, considers scenarios of DER uptake. Furthermore, the uncertainty associated with the operation of such networks, particularly the location and capacity of DERs, must be considered. This paper discusses the requirements for probabilistic network planning considering DER penetration. The results from comparative studies of selected approaches validates the inadequacy of old approaches and demonstrates that stochastic allocation of DER must be considered, else the designed systems are prone to be non-compliant under some loading scenarios.

ABSTRACT. Peer-to-peer electricity trading between consumers, producers and/or prosumers located in a low voltage distribution grid is a concept that goes well with the trends of democratization, decarbonization and decentralization in the power sector. However, the effects of peer-to-peer electricity trading on voltage levels in distribution grids are still in the early stage of research. The aim of this work is to investigate effects of a near real-time peer-to-peer electricity trading in a distribution grid on voltage levels. It is analyzed if a contribution to the maintenance of the voltages within limits can be achieved without security-constrained unit commitment calculations for the observed time horizon and without security-constrained economic dispatch calculations for each trading period. The peer-to-peer electricity trading is simulated as an auction-based local market and applied on the modified IEEE European Low Voltage Test Feeder where the effects of local electricity trading on voltage levels are studied for different elasticities of demand offering curves.

ABSTRACT. This paper proposes optimum settings and curve selections of directional overcurrent relays (DOCRs) in interconnected sub-transmission systems using metaheuristic genetic algorithm (GA). In this paper, all the relays are considered to be associated with three variables which are time multiplier-setting (TMS), plug-setting (PS) and curve-setting (CS) to obtain their correct operating times. The TMS and PS of all the relays are considered as continuous variables which are possible with numerical/digital relays whereas the CS is considered as a discrete variable and are associated with the selection of the characteristics of the relay among normal inverse (NI), very inverse (VI) and extremely inverse (EI). The proposed coordination approach has been tested on the IEEE 14-bus sub-transmission system and the importance of curve selection has been discussed using numerical analysis. Further, the results obtained using GA have been validated by comparing with that obtained by Particle swarm optimization. The proposed approach considering mixed characteristic curves of NI, VI, and EI gives the best settings of DOCRs with much-improved protection coordination.