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Library of Congress Cataloging-in-Publication Data
ISBN 9781119710790
Cover image: Solar Panel Technology | Vtt Studio | Dreamstime.com
Cover design by Kris Hackerott
Set in size of 11pt and Minion Pro by Manila Typesetting Company, Makati, Philippines
3.5.9
3.5.10
5.3
5.4
5.5
Saravanan, S., Pandiyan, P., Chinnadurai, T., Ramji, Tiwari., Prabaharan, N., Senthil Kumar, R. and Lenin Pugalhanthi, P.
6.3
6.4
6.5
6.10.2.4
8 AC Microgrid
Ali M. Eltamaly, Yehia Sayed Mohamed, Abou-Hashema M. El-Sayed and Amer Nasr A. Elghaffar
8.3
9 A Numerical Approach for Estimating Emulated Inertia With
Shubham Tiwari, Jai Govind
R. Zahira, D. Lakshmi and C.N. Ravi
11
T. Eswara Rao, Krishna Mohan Tatikonda, S. Elango and J. Charan Kumar
12 Power Quality
CH. S. Balasubrahmanyam, Om Hari Gupta and Vijay K. Sood
Power electronics—as a broader technology—fits into modern digital power e-grid, transport, and renewable energy. Editing a book on the current requirements and prospective scope is a challenge to qualify and accomplish according to the market requirements and end-user benefits. It is my pleasure to write a foreword to this book edited/written by my colleagues from Aalborg University, Esbjerg, Denmark and Anna University, Chennai, India—“Microgrid Technologies,” which is giving viable solutions to the demands. With my read-through of the book, I have identified that the content is inventive and enriched with techno-fiscals, a model for upcoming activities for the academic, researchers, and industrialists, from whom we hope the microgrids will be adapted in their work.
Microgrids are a digital power electronics innovation in new energy operation for electrical energy management with grid-connected or island mode configuration within micro-, macro-, or even nano-energy requirements. A methodical manner and straightforward presentation with all prospects, this book is made up of architectures, theories of AC and DC microgrids, sociocommercial features, energy stream and operation, renewable integration, control techniques, application of artificial intelligence, and analytical simulation examples of microgrid technologies. It is a unified contribution by international authors from Europe, India, Canada, South Africa, Egypt, and Thailand.
Critical Subjects Covered in This Volume
• The state of the art in renewable energy system-based microgrid includes grid-connected and island structures, distributed energy storage schemes, energy and power management, load flow evaluation, protection, and coordination.
• Digital techniques, Internet of Things (IoT), Artificial Intelligence (AI), communications, etc. are also included.
Foreword
• Detailed studies culminate with the analytical result for frequency regulation in a low inertia system, PSO algorithm-based UPQC controller, and power quality enhancement too.
• Modeling of smart meters using the most recent technologies of “game theory,” “relaxation algorithm,” “bi-level algorithm,” and “Nikaido–Isoda formulation” for energy exchange centers and bidding strategies—a scope/look to the future digitalized microgrid in renewables is also an interesting prospect of the book.
From an overall perspective, this book presents the fundamental concepts of modernizing the microgrids as a thirst area of more ample opportunity, and contributes to original research study findings. Therefore, this book is a handy source, offering new interest for electrical power engineers and renewable operators/state regulators.
This book is a strong addition for readers to enjoy sharing proficiency in the exciting field of microgrids. Finally, I congratulate the Editors, Contributors, and the Wiley-Scrivener Publishing, USA, for the work to bring this into reality with prompt and sharp-quality delivery.
Enjoy reading the book.
Prof. Frede Blaabjerg, Fellow IEEE
Villum Investigator Full Professor IEEE President – Power Electronics Society Center of Reliable Power Electronics (CORPE) Department of Energy Technology Aalborg University, Denmark
Acknowledgements
Foremost, thanks to the Almighty for his everlasting love throughout this endeavor.
The Acknowledgements section is always a place to appreciate the dedication, commitment, resources, and timely solution either with the digital platform or a real-time medium; timely support and bond of encouragement are vital tools for teachers and researchers from their Institution.
In these regards, we, editors, express our sincere thanks to Mr. S. Rajkumar, Executive, JLL, Bengaluru, India; Ms. A. Thaiyal Nayagi, Lecturer, Rane Polytechnic College, Trichy, India; Mr. S. Muthukumaran, Director, TECH Engineering Services, Chennai, India; Mr. K. Balaji, Sr. Electrical Engineer, Sree Nandees Technologies, Chennai, India; Mr. K. Sasikumar, Electrical Engineer, Mott MacDonald, Noida, India; Center for Bioenergy and Green Engineering, Department of Energy Technology, Aalborg University, Esbjerg, Denmark, and Department of Electrical and Electronics Engineering, College of Engineering Guindy, Anna University, Chennai, India.
We, editors, got the full support and executed the task promptly where our Institution devoted the time and liberty for enhancement with research in particular to make this book a great success.
I wish one and all who devoted time and effort for the grand success with the book.
Warm regards, Editors
1
A Comprehensive Review on Energy Management in Micro-Grid System
Sanjay Kumar1*, R. K. Saket2, P. Sanjeevikumar3 and Jens Bo Holm-Nielsen3
1Electrical & Electronics Engineering Department, Centurion University of Technology and Management, Odisha, India
2Electrical Engineering Department, IIT (BHU) Varanasi, India
3Center for Bioenergy and Green Engineering, Department of Energy Technology, Aalborg University, Esbjerg, Denmark
Abstract
Since the last decades there has been a huge exploitation of non-conventional (renewable) energy resources which has increased significantly. A Micro-Grid (MG) presents an appropriate concept to integrate local resources of renewable energy with Storage System of Energy (SSE) and are synchronized to supply the customers’ requirement in different circumstances. Apart from this, the Management System of Energy (MSE) has been analyzed for allocating the output power from the Distributed Generator (DG) units optimally. It also satisfies the local demand, regulates the voltage and frequency of the smart MG, and secures a flat switching between modes, connected to grid and mode of islanded operation. In this article the authors have made an outmost effort about the area of MG–MSE, evolved in the current framework, discussing the storage units and generation of MG, the importance of Electric Vehicles (EVs) as a backup unit, combined heat and power for supplying the thermal requirements, objectives function of MG-MSE and constraints of the systems and current algorithms of optimization.
Keywords: Management System of Energy (MSE), Micro-Grid (MG), Electric Vehicles (EVs), Heat and Power Combination (HPC), optimization algorithms
Previously, fossil fuel represents the popular source of electricity, creating emissions of gaseous pollutant in our environment. This led to the advent of renewable energy sources, which provided clean energy and have become the most suitable choice for mitigating the dependency on fossil fuel as it also decreases the Greenhouse effect from the atmosphere. The other natural resources included solar, wind, ocean, biomass, hydro, and geothermal, etc. and were capable of producing electrical energy.
As per the renewable global status report of 2017, the power sector is mainly concerned about the renewable technologies policy, which gives a facility of integration of it into the existing energy systems. Figure 1.1 shows the universal electricity creation until the end of 2016, and also shows that about 30.28% of the entire power is depicted by means of the renewable sources. The estimation is about 2,017 GW out of 6,660 GW the total global electrical energy capacity. Hydropower takes the 1st position in the production of RE.
Clearly, it is shown in Figure 1.2 that about 16.46% of the total power is supplied by the hydropower. It is 54.34% of the RE. The wind power follows it, which is about 7.3% of the total and 24.15% of renewable sources. Then comes Photovoltaic (PV) power (15.02% of RE), about 4.55% of total power capacity, bio-power (5.55% of RE) is about 1.7%, and others are 0.9%. But in 2016, the newly implemented renewable energy is increased by solar (PV) power (47%), wind power (15.5%) and hydropower (9) compared to 2015 [1].
Figure 1.3 shows the consumption of energy sources like natural gas, coal, renewable sources, nuclear, petroleum and other liquid fuels from
Figure 1.1 The renewable global status report.
the year 1090 to 2040 [2]. According to this, consumption of renewable sources is going to increase by 30% in the duration from 2015 to 2040.
Nowadays, maximum research is going on the utility of renewable energy. Micro-grid integration has taken the maximum concentration of researchers. A micro-grid (MG) is a distributed network that includes different possible distributed resources of energy, which can be considered as a single system, that can be optimizable, means can be balanced with generations and loads with a suitable storage system. It is also capable of doing work independently with or without connection with the utility power grid [3].
A micro-grid is a network or an association of local electrical generation resources connected through a common point known as PCC.
Figure 1.2 Consumption of renewable energy sources.
Figure 1.3 Intensification of various energy sources from 1990 to 2040.
The micro-grid has one or more renewable generation units, conventional power generation system, the electrical storage system (ESS), the thermal storage system (TSS), electrical loads, and thermal loads. The conventional power generation system can consist of the micro turbine (MT), diesel generator set, etc. Similarly, in renewable generation units, we can make a photovoltaic (PV) generation system, wind turbines, biomass and hydrokinetic system, etc.There are two manners of operation of a microgrid namely, connected to grid manner, and the other one is island manner. In GC mode a microgrid is in link with the conventional power grid. It is capable of participating in the energy market as a seller or buyer that can exchange energy with the utility. However, in the islanded manner, micro-grid functions as an autonomous body, as disconnected from the utility network. The island condition occurs due to several reasons such as geographical position on earth, brownout and economic issues.
Generally, the microgrids face a problem of supplying demand properly due to insufficient energy generation. This problem is because of the irregularity of loads and the RE sources [4]. So, a management system is required to deal with the problem. This management system is called a management system of energy (MSE).
The management system of energy (MSE) is the collection of different control approaches and different active, ongoing exercises along with hardware and software to mitigate the energy management objectives problems. It is a multiple functionary system. It is a system which distributes the generated power optimally and economically to the load with proper voltage regulation and frequency regulation of the micro-grid. So, we can get a smooth changeover between connected to grid manner and isolated manner of micro-grid systems, according to micro-grid components and real-time load conditions of operation. This system can be used to get high-quality power, sustainability, reliability and environmentally friendly power source.
Due to this, researchers started focusing extensively on MSE strategies for various micro-grids ranging from small home (small scale) to cities or towns (large scale) as shown in the different scales of MG of Figure 1.4.
Exploration has started on a study of the practicability of the parts of micro-grid, and it is modeled by scheduling the DGs, and forecasting the data of environmental conditions such as irradiance of sunray, speed of wind flow and water speed, forecast of energy demand and on availability optimization algorithms in the intention of cost-effective benefits with minimum impact on the atmosphere. Figure 1.5 shows the central micro-grid arrangement and components related to the energy management system. It shows that the
research is mainly focused on the resolution of different problems regarding the micro-grid by means of an energy management system.
This is a review of the different features of micro-grid and management of energy that are presented in various current topics, starting from various units of MG, synchronization of components to the recent optimization methodology with system limitations and objective functions for MSE.
Afterwards, the different configuration and components of micro-grid are deployed in Section 1.2. Here the different structures used in an energy management system with various distributed energy sources, various storage systems and different type of load or the consumer behavior are illustrated. Followed by Section 1.3, it depicts the MG–MSE and different modes of operation. Further, Section 1.4 discusses about the recent
Figure 1.4 Various ranges of MG.
Solar Photovoltaics
Figure 1.5 Components of micro-grid.
techniques and algorithms used for optimization in energy management systems. Finally, Section 1.5 concludes the different sections and further deliberates the strategy for further research in this area.
1.2 Generation and Storage System in MicroGrid
1.2.1
Distributed Generation of Electrical Power
In recent years, a great number of researchers are discussing the issues in micro-grids. Nowadays, the verities of micro-grid structures have been presented in the literature. In micro-grid the different distributed generations are utilized because of its geographical characteristic, economic benefits, environmental condition and impact on the surrounding. In Ref. [5], there is a discussion on predictive MSE with its control strategies and communication of micro-grid to the independent utility grid. A 1.5 MW wind energy associated with the battery as a storage system is analyzed. In Ref. [6] a hybrid hydrokinetic system HKT battery is used in GC mode. The surplus power of HKT is utilized for charging a battery or trade to the grid. Whether the power will be sold to the main grid or not is determined by the charge condition of the battery and the principle of the utility grid network. The power requirement of the load is provided by the HKT. The excess power is utilized to charge the storage body. Then also, if there is an excess quantity of power, that can return back to the utility grid network. However, the utility grid supplies the load directly when the distributed generation system and the battery can’t entirely meet the load demand.
The universally used energy storage system is the battery. The battery system also has some limitations, as some charging and discharging current issues and unreliability according to the lifespan of the battery. So, techno-electronic indexes of micro-grid-based hybrid renewable energy resources are significantly increased by applying the distributed system of the generation with the storage system of energy [7]. Ref. [8] is a study of hybrid solar power as PV and diesel power in a distributed system supplying a load of a rural school in Ethiopia. The paper has compared the hybrid PV/Diesel distributed system with the storage system to the distributed generation system without storage as the net instantaneous rate of energy. Here a software named Homer is applied for analysis. The result was concluded that the hybrid distributed generation system with storage is having technical and economic advantages than that without storage. In Ref. [9] the authors proposed that the energy management system for hybrid micro-grid consist of photovoltaic and wind power as renewable energy
sources (RES) and fuel cell (Hydrogen cell), ultracapacitor or battery as storage system of energy (SSE).
1.2.2 Incorporation of Electric Car in Micro-Grid as a Device for Backup
Nowadays the incorporation of an electric vehicle with micro-grid is viral because of its effect of low emission, inexpensive charging and decreased usage of conventional fuels. The electric car with MG can function in carto-grid (C2G) mode or grid-to-car (G2C) mode. In Ref. [10] planned power management is proposed in the MG, including storage systems categorized into two types: regenerative fuel cell (RFC) and electric car (EV). That paper approaches with multi-goal optimization to minimize operational cost, line losses and maximise the value of energy stored in terms of RFC and EC. There are two functioning schemes planned for EC working in C2G mode to decrease the net running cost of the system. The combination of particle swarm skim of optimization as well as front and back sweep algorithm is used to solve complication, non-linear action and multidimensional property of the objective function. In Ref. [11] a large-scale electric vehicle charging station is proposed by the author, in which the required power is supplied by solar and wind power. Here both the PV and wind work with a unified MPPT technique. In Ref. [12] the author incorporated the plug-in charger of the electric vehicle in the distribution grid in both directions by using various converters. The bidirectional converters are coupled to the capacitor at the link with DC. The grid voltage may be regulated in the C2G configuration using the capacitor at the link with DC, which provides compensation for reactive power, which avoids the risk of voltage sag in the main. The mixed charging electrical car battery is used for peak load shaving and load levelling. Ref. [13] illustrates a real application of electric vehicle charging station along with a storage system of energy, which is a battery of Lithium polymer. Investigational research is done in Italy at the power and Sustainable Economic Development labs for innovative Technologies. The outcome shows the new performance of the ECs in the height of energy shaving action, as compared to the utility grid. A resiliency-based Energy Management System of islanded operation of micro-grid is presented in Ref. [14]. Here the case studied is about microgrid (MG) consisting of PV generation farms and WT generation farms both having storage system of energy (SSE) and distributed generation system. Based on the study, the researchers used 25 plug-in hybrid electric cars as adaptable load and supply to replicate the scheme of demand response in an optimal way, so the ECs in G2V manner are used as
