• Energy Research

Three-phase grid-connected photovoltaic (PV) systems are most dominant in power system distribution applications. The LC filters are commonly employed in the PV grid-connected inverters. This paper presents a new adaptive fuzzy control for an inverter connected to the grid through an LC filter. The proposed controller exploits the concept of input-output feedback linearization and the approximation capability of fuzzy systems. The control objective is to control the inverter current components to prescribed reference values. The closed-loop system stability and the updating laws of the controller parameters are determined via Lyapunov analysis. Finally, the proposed controller is simulated, and results are presented to validate the effectiveness of the designed controller under different system disturbance and parameter uncertainties.

Advances in technology and population growth are two factors responsible for increasing electricity consumption, which directly increases the production of electrical energy. Additionally, due to environmental, technical and economic constraints, it is challenging to meet demand at certain hours, such as peak hours. Therefore, it is necessary to manage network consumption to modify the peak load and tackle power system constraints. One way to achieve this goal is to use a demand response program. The home energy management system (HEMS), based on advanced internet of things (IoT) technology, has attracted the special attention of engineers in the smart grid (SG) field and has the tasks of demand-side management (DSM) and helping to control equality between demand and electricity supply. The main performance of the HEMS is based on the optimal scheduling of home appliances because it manages power consumption by automatically controlling loads and transferring them from peak hours to off-peak hours. This paper presents a multi-objective version of a newly introduced metaheuristic called the bald eagle search optimization algorithm (BESOA) to discover the optimal scheduling of home appliances. Furthermore, the HEMS architecture is programmed based on MATLAB and ThingSpeak modules. The HEMS uses the BESOA algorithm to find the optimal schedule pattern to reduce daily electricity costs, reduce the PAR, and increase user comfort. The results show the suggested system’s ability to obtain optimal home energy management, decreasing the energy cost, microgrid emission cost, and PAR (peak to average ratio).

This manuscript presents a robust tracking (servomechanism) controller for linear time-invariant (LTI) islanded (autonomous, isolated) microgrid voltage control. The studied microgrid (MG) consists of many distributed energy resources (DERs) units, each using a voltage-sourced converter (VSC) for the interface. The optimal tracker design uses the ellipsoidal approximation to the invariant sets. The MG system is decomposed into different subsystems (DERs). Each subsystem is affected by the rest of the system that is considered as a disturbance to be rejected by the controller. The proposed tracker (state feedback integral control) rejects bounded external disturbances by minimizing the invariant ellipsoids of the MG dynamics. A condition to design decentralized controllers is derived in the form of linear matrix inequalities. The proposed controller is characterized by rapid transient response, and zero error in the steady state. A robustness analysis of the control strategy (against load changes, load unbalances, etc.) is carried out. A MATLAB/SimPowerSystems (R2017b, MathWorks, Natick, MA, USA) simulation of the case study confirm the robustness of the proposed controller.

Inverter-based distributed generators (DGs) have been customarily used for voltage unbalance (VU) mitigation in microgrids. The sole dependency on DGs for VU mitigation may not be justified, particularly in islanded microgrids. Demand side management can be a potential candidate for VU mitigation in microgrids. Therefore, this paper presents a new VU mitigation scheme for an islanded microgrid by coordinating photovoltaic (PV) grid-tied inverters, and thermostatically controlled loads (TCLs). A negative sequence compensation loop working in parallel with a positive sequence compensation loop is designed for PV inverters for VU mitigation. Also, a voltage dependent model of TCLs, unlike the conventional one, along with the control strategy for VU mitigation is presented. The proposed control of TCLs not only minimizes VU, and hence, increases the dynamic reactive power reserve of the inverter based DGs, but also effectively maintains the customers’ thermal comfort. The proposed VU mitigation scheme is studied with comprehensive simulations in PSCAD/EMTDC, and is verified using a real-time digital simulator, OPAL-RT. Simulations and real-time results of the proposed scheme demonstrated the regulation of VU factor within the permissible range defined by IEC and CIGRE Working Group 36.07.

Power system stability studies are required for both planning and operation of power networks. Its importance has become more vital due to high dimensionality and complexity of modern power systems. In this paper a review of power system stability is presented. The effects of renewable energy sources to the integrated power systems are highlighted. The paper considers the main interconnected system (MIS) of the Sultanate of Oman as a case study. The transient stability of MIS 2015 maximum peak model is examined using Power Factory DigSILENT. The installation of Power System Stability (PSS) at Sur power station satisfactorily enhanced the overall stability of MIS.

This paper proposes an approach for accurate wind speed forecasting. While previous works have proposed approaches that have either underperformed in accuracy or were too computationally intensive, the work described in this paper was implemented using a computationally efficient model. This model provides wind speed nowcasting using a combination of perturbed observation ensemble networks and artificial neural networks. The model was validated and evaluated via simulation using data that were measured from wind masts. The simulation results show that the proposed model improved the normalized root mean square error by 20.9% compared to other contending approaches. In terms of prediction interval coverage probability, our proposed model shows a 17.8% improvement, all while using a smaller number of neural networks. Furthermore, the proposed model has an execution time that is one order of magnitude faster than other contenders.

Les systèmes énergétiques sont dynamiques et en transition en raison des ressources énergétiques alternatives, des innovations technologiques, de la demande, des coûts et des conséquences environnementales. Les combustibles fossiles sont les sources de production d'énergie traditionnelle, mais ils sont progressivement passés aux technologies innovantes actuelles, en mettant l'accent sur les ressources renouvelables comme le solaire et l'éolien. Malgré des augmentations constantes des prix de l'énergie, les demandes des clients augmentent rapidement en raison de l'augmentation de la population, du développement économique, de la consommation par habitant, de l'approvisionnement dans des endroits éloignés et sous forme statique pour les machines et les appareils portables. Le stockage d'énergie peut permettre une production et une livraison flexibles d'électricité stable pour répondre aux demandes des clients. Les exigences en matière de stockage d'énergie deviendront le triple des valeurs actuelles d'ici 2030 pour lesquelles des dispositifs et des systèmes très spéciaux sont nécessaires. L'objectif de la présente recherche d'examen est de comparer et d'évaluer les dispositifs et les systèmes actuellement utilisés et prévus pour l'avenir. Les questions économiques et environnementales ainsi que les défis et les limites ont été élaborés grâce à une consultation approfondie et forte de la littérature, des recherches antérieures, des rapports et des revues. Les technologies telles que les batteries à flux, les supercondensateurs, LES PME (stockage d'énergie magnétique supraconductrice), les FES (Flywheel Energy Storage), les PHS (stockage hydraulique par pompage), les tes (stockage d'énergie thermique), les CAE (stockage d'énergie à air comprimé) et les HES (stockage d'énergie hybride) ont été discutées. Cet article peut contribuer à guider les décideurs et les praticiens s'ils veulent sélectionner les dispositifs et systèmes de stockage d'énergie les plus récents et les plus innovants pour leurs réseaux et d'autres utilisations associées comme les machines et les appareils portables. Les caractéristiques, les avantages, les limites, les coûts et les considérations environnementales ont été comparés à l'aide de tableaux et de démonstrations pour faciliter leur décision finale et la gestion des problèmes émergents. Ainsi, les résultats de cette étude d'examen peuvent s'avérer très utiles pour diverses parties prenantes du secteur de l'énergie. Los sistemas energéticos son dinámicos y transitorios debido a los recursos energéticos alternativos, las innovaciones tecnológicas, la demanda, los costes y las consecuencias ambientales. Los combustibles fósiles son las fuentes de generación de energía tradicional, pero se ha hecho una transición gradual a las tecnologías innovadoras actuales con énfasis en los recursos renovables como la solar y la eólica. A pesar de los constantes aumentos en los precios de la energía, las demandas de los clientes están aumentando rápidamente debido a un aumento en las poblaciones, el desarrollo económico, el consumo per cápita, el suministro en lugares remotos y en formas estáticas para máquinas y dispositivos portátiles. El almacenamiento de energía puede permitir la generación flexible y el suministro de electricidad estable para satisfacer las demandas de los clientes. Los requisitos para el almacenamiento de energía se convertirán en el triple de los valores actuales para 2030, para lo cual se requieren dispositivos y sistemas muy especiales. El objetivo de la investigación de revisión actual es comparar y evaluar los dispositivos y sistemas actualmente en uso y anticipados para el futuro. Los problemas económicos y ambientales, así como los desafíos y limitaciones, se han elaborado a través de una consulta profunda y sólida de la literatura, investigaciones previas, informes y revistas. Se han discutido las tecnologías como baterías de flujo, supercondensadores, SME (Superconducting magnetic energy storage), FES (Flywheel Energy Storage), PHS (Pumped hydro storage), tes (Thermal Energy Storage), caes (Compressed Air Energy Storage) y HES (Hybrid energy storage). Este artículo puede contribuir a guiar a los responsables de la toma de decisiones y a los profesionales si desean seleccionar los dispositivos y sistemas de almacenamiento de energía más recientes e innovadores para sus redes y otros usos asociados, como máquinas y dispositivos portátiles. Las características, ventajas, limitaciones, costos y consideraciones ambientales se han comparado con la ayuda de tablas y demostraciones para facilitar su decisión final y la gestión de los problemas emergentes. Por lo tanto, los resultados de este estudio de revisión pueden resultar muy útiles para varias partes interesadas del sector energético. Energy systems are dynamic and transitional because of alternative energy resources, technological innovations, demand, costs, and environmental consequences. The fossil fuels are the sources of traditional energy generation but has been gradually transitioned to the current innovative technologies with an emphasis on renewable resources like solar, and wind. Despite consistent increases in energy prices, the customers' demands are escalating rapidly due to an increase in populations, economic development, per capita consumption, supply at remote places, and in static forms for machines and portable devices. The energy storage may allow flexible generation and delivery of stable electricity for meeting demands of customers. The requirements for energy storage will become triple of the present values by 2030 for which very special devices and systems are required. The objective of the current review research is to compare and evaluate the devices and systems presently in use and anticipated for the future. The economic and environmental issues as well as challenges and limitations have been elaborated through deep and strong consultation of literature, previous research, reports and journal. The technologies like flow batteries, super capacitors, SMES (Superconducting magnetic energy storage), FES (Flywheel Energy Storage), PHS (Pumped hydro storage), TES (Thermal Energy Storage), CAES (Compressed Air Energy Storage), and HES (Hybrid energy storage) have been discussed. This article may contribute to guide the decision-makers and the practitioners if they want to select the most recent and innovative devices and systems of energy storage for their grids and other associated uses like machines and portable devices. The characteristics, advantages, limitations, costs, and environmental considerations have been compared with the help of tables and demonstrations to ease their final decision and managing the emerging issues. Thus, the outcomes of this review study may prove highly useful for various stakeholders of the energy sector. تتسم أنظمة الطاقة بالديناميكية والانتقال بسبب موارد الطاقة البديلة والابتكارات التكنولوجية والطلب والتكاليف والعواقب البيئية. الوقود الأحفوري هو مصادر توليد الطاقة التقليدية ولكن تم نقله تدريجياً إلى التقنيات المبتكرة الحالية مع التركيز على الموارد المتجددة مثل الطاقة الشمسية وطاقة الرياح. على الرغم من الزيادات المستمرة في أسعار الطاقة، فإن طلبات العملاء تتصاعد بسرعة بسبب الزيادة في عدد السكان، والتنمية الاقتصادية، واستهلاك الفرد، والإمدادات في الأماكن النائية، وفي أشكال ثابتة للآلات والأجهزة المحمولة. قد يسمح تخزين الطاقة بتوليد وتوصيل الكهرباء المستقرة بشكل مرن لتلبية متطلبات العملاء. ستصبح متطلبات تخزين الطاقة ثلاثة أضعاف القيم الحالية بحلول عام 2030 والتي تتطلب أجهزة وأنظمة خاصة جدًا. الهدف من بحث المراجعة الحالي هو مقارنة وتقييم الأجهزة والأنظمة المستخدمة حاليًا والمتوقعة للمستقبل. تم توضيح القضايا الاقتصادية والبيئية وكذلك التحديات والقيود من خلال التشاور العميق والقوي للأدبيات والبحوث السابقة والتقارير والمجلات. تمت مناقشة التقنيات مثل بطاريات التدفق، والمكثفات الفائقة، والشركات الصغيرة والمتوسطة (تخزين الطاقة المغناطيسية فائقة التوصيل)، و FES (تخزين طاقة الحدافة)، و PHS (التخزين المائي المضخ)، و TES (تخزين الطاقة الحرارية)، و CAES (تخزين طاقة الهواء المضغوط)، و HES (تخزين الطاقة الهجين). قد تساهم هذه المقالة في توجيه صانعي القرار والممارسين إذا كانوا يرغبون في اختيار أحدث الأجهزة والأنظمة المبتكرة لتخزين الطاقة لشبكاتهم والاستخدامات الأخرى المرتبطة بها مثل الآلات والأجهزة المحمولة. تمت مقارنة الخصائص والمزايا والقيود والتكاليف والاعتبارات البيئية بمساعدة الجداول والعروض التوضيحية لتسهيل قرارها النهائي وإدارة القضايا الناشئة. وبالتالي، قد تكون نتائج هذه الدراسة الاستعراضية مفيدة للغاية لمختلف أصحاب المصلحة في قطاع الطاقة.