Editorial

7 pages, 179 KiB

Open AccessEditorial

Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid

by Surender Reddy Salkuti

Energies 2022, 15(18), 6667; https://doi.org/10.3390/en15186667 - 13 Sep 2022

Cited by 56 | Viewed by 2364

Future grid refers to the next generation of the electrical grid, which will enable smart integration of conventional, renewable, and distributed power generation, energy storage, transmission and distribution, and demand management [...] Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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26 pages, 5427 KiB

Open AccessArticle

Enabling Technologies for Energy Communities: Some Experimental Use Cases

by Daniele Menniti, Anna Pinnarelli, Nicola Sorrentino, Pasquale Vizza, Giuseppe Barone, Giovanni Brusco, Stefano Mendicino, Luca Mendicino and Gaetano Polizzi

Energies 2022, 15(17), 6374; https://doi.org/10.3390/en15176374 - 31 Aug 2022

Cited by 15 | Viewed by 1985

Abstract

It is known that the energy transition can be achieved not only with the use of renewable energy sources but also with a new conception and management of the electricity system. Renewable energy communities are then introduced as organizations for maximizing the self-consumption [...] Read more.

It is known that the energy transition can be achieved not only with the use of renewable energy sources but also with a new conception and management of the electricity system. Renewable energy communities are then introduced as organizations for maximizing the self-consumption of energy produced from renewable energy sources. To ensure that these energy communities can operate, there is a need for enabling technologies that allow for monitoring, data and algorithms processing as well as the enabling of the same algorithms. There exists a huge confusion in the actual technologies useful to implement the energy communities. This paper first describes and groups the main enabling technologies, analyzing the services that can be offered. The scope is to emphasize the importance of having accurate, efficient and effective technologies that allow the implementation of such communities, underlining how such technologies interact with each other. Using such technologies is important to observing the possible technical and energetic results; indeed, use cases concerning the use of these enabling technologies are proposed and analyzed, showing their operating and their good environmental and energy impact. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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19 pages, 7351 KiB

Open AccessArticle

Optimal Scheduling of Energy Storage System Considering Life-Cycle Degradation Cost Using Reinforcement Learning

by Wonpoong Lee, Myeongseok Chae and Dongjun Won

Energies 2022, 15(8), 2795; https://doi.org/10.3390/en15082795 - 11 Apr 2022

Cited by 8 | Viewed by 2009

Abstract

Recently, due to the ever-increasing global warming effect, the proportion of renewable energy sources in the electric power industry has increased significantly. With the increase in distributed power sources with adjustable outputs, such as energy storage systems (ESSs), it is necessary to define [...] Read more.

Recently, due to the ever-increasing global warming effect, the proportion of renewable energy sources in the electric power industry has increased significantly. With the increase in distributed power sources with adjustable outputs, such as energy storage systems (ESSs), it is necessary to define ESS usage standards for an adaptive power transaction plan. However, the life-cycle cost is generally defined in a quadratic formula without considering various factors. In this study, the life-cycle cost for an ESS is defined in detail based on a life assessment model and used for scheduling. The life-cycle cost is affected by four factors: temperature, average state-of-charge (SOC), depth-of-discharge (DOD), and time. In the case of the DOD stress model, the life-cycle cost is expressed as a function of the cycle depth, whose exact value can be determined based on fatigue analysis techniques such as the Rainflow counting algorithm. The optimal scheduling of the ESS is constructed considering the life-cycle cost using a tool based on reinforcement learning. Since the life assessment cannot apply the analytical technique due to the temperature characteristics and time-dependent characteristics of the ESS SOC, the reinforcement learning that derives optimal scheduling is used. The results show that the SOC curve changes with respect to weight. As the weight of life-cycle cost increases, the ESS output and charge/discharge frequency decrease. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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19 pages, 4231 KiB

Open AccessArticle

Spectral Kurtosis Based Methodology for the Identification of Stationary Load Signatures in Electrical Signals from a Sustainable Building

by Luis A. Romero-Ramirez, David A. Elvira-Ortiz, Rene de J. Romero-Troncoso, Roque A. Osornio-Rios, Angel L. Zorita-Lamadrid, Sergio L. Gonzalez-Gonzalez and Daniel Morinigo-Sotelo

Energies 2022, 15(7), 2373; https://doi.org/10.3390/en15072373 - 24 Mar 2022

Cited by 3 | Viewed by 1563

Abstract

The increasing use of nonlinear loads in the power grid introduces some unwanted effects, such as harmonic and interharmonic contamination. Since the existence of spectral contamination causes waveform distortion that may be harmful to the loads that are connected to the grid, it [...] Read more.

The increasing use of nonlinear loads in the power grid introduces some unwanted effects, such as harmonic and interharmonic contamination. Since the existence of spectral contamination causes waveform distortion that may be harmful to the loads that are connected to the grid, it is important to identify the frequency components that are related to specific loads in order to determine how relevant their contribution is to the waveform distortion levels. Due to the diversity of frequency components that are merged in an electrical signal, it is a challenging task to discriminate the relevant frequencies from those that are not. Therefore, it is necessary to develop techniques that allow performing this selection in an efficient way. This paper proposes the use of spectral kurtosis for the identification of stationary frequency components in electrical signals along the day in a sustainable building. Then, the behavior of the identified frequencies is analyzed to determine which of the loads connected to the grid are introducing them. Experimentation is performed in a sustainable building where, besides the loads associated with the normal operation of the building, there are several power electronics equipment that is used for the electric generation process from renewable sources. Results prove that using the proposed methodology it is possible to detect the behavior of specific loads, such as office equipment and air conditioning. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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31 pages, 7910 KiB

Open AccessArticle

Impact of Demand Response on Optimal Sizing of Distributed Generation and Customer Tariff

by Krishna Mohan Reddy Pothireddy, Sandeep Vuddanti and Surender Reddy Salkuti

Energies 2022, 15(1), 190; https://doi.org/10.3390/en15010190 - 28 Dec 2021

Cited by 31 | Viewed by 2706

Abstract

Due to the surge in load demand, the scarcity of fossil fuels, and increased concerns about global climate change, researchers have found distributed energy resources (DERs) to be alternatives to large conventional power generation. However, a drastic increase in the installation of distributed [...] Read more.

Due to the surge in load demand, the scarcity of fossil fuels, and increased concerns about global climate change, researchers have found distributed energy resources (DERs) to be alternatives to large conventional power generation. However, a drastic increase in the installation of distributed generation (DGs) increases the variability, volatility, and poor power quality issues in the microgrid (MG). To avoid prolonged outages in the distribution system, the implementation of energy management strategies (EMS) is necessary within the MG environment. The loads are allowed to participate in the energy management (EM) so as to reduce or shift their demands to non-peak hours such that the maximum peak in the system gets reduced. Therefore, this article addresses the complication of solutions, merits, and demerits that may be encountered in today’s power system and encompassed with demand response (DR) and its impacts in reducing the installation cost, the capital cost of DGs, and total electricity tariff. Moreover, the paper focuses on various communication technologies, load clustering techniques, and sizing methodologies presented. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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24 pages, 4991 KiB

Open AccessFeature PaperArticle

Optimal Energy Management of a Campus Microgrid Considering Financial and Economic Analysis with Demand Response Strategies

by Haseeb Javed, Hafiz Abdul Muqeet, Moazzam Shehzad, Mohsin Jamil, Ashraf Ali Khan and Josep M. Guerrero

Energies 2021, 14(24), 8501; https://doi.org/10.3390/en14248501 - 16 Dec 2021

Cited by 24 | Viewed by 3527

Abstract

An energy management system (EMS) was proposed for a campus microgrid (µG) with the incorporation of renewable energy resources to reduce the operational expenses and costs. Many uncertainties have created problems for microgrids that limit the generation of photovoltaics, causing an upsurge in [...] Read more.

An energy management system (EMS) was proposed for a campus microgrid (µG) with the incorporation of renewable energy resources to reduce the operational expenses and costs. Many uncertainties have created problems for microgrids that limit the generation of photovoltaics, causing an upsurge in the energy market prices, where regulating the voltage or frequency is a challenging task among several microgrid systems, and in the present era, it is an extremely important research area. This type of difficulty may be mitigated in the distribution system by utilizing the optimal demand response (DR) planning strategy and a distributed generator (DG). The goal of this article was to present a strategy proposal for the EMS structure for a campus microgrid to reduce the operational costs while increasing the self-consumption from green DGs. For this reason, a real-time-based institutional campus was investigated here, which aimed to get all of its power from the utility grid. In the proposed scenario, solar panels and wind turbines were considered as non-dispatchable DGs, whereas a diesel generator was considered as a dispatchable DG, with the inclusion of an energy storage system (ESS) to deal with solar radiation disruptions and high utility grid running expenses. The resulting linear mathematical problem was validated and plotted in MATLAB with mixed-integer linear programming (MILP). The simulation findings demonstrated that the proposed model of the EMS reduced the grid electricity costs by 38% for the campus microgrid. The environmental effects, economic effects, and the financial comparison of installed capacity of the PV system were also investigated here, and it was discovered that installing 1000 kW and 2000 kW rooftop solar reduced the GHG generation by up to 365.34 kg CO₂/day and 700.68 kg CO₂/day, respectively. The significant economic and environmental advantages based on the current scenario encourage campus owners to invest in DGs and to implement the installation of energy storage systems with advanced concepts. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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20 pages, 19113 KiB

Open AccessArticle

Multiobjective Scheduling of Hybrid Renewable Energy System Using Equilibrium Optimization

by Salil Madhav Dubey, Hari Mohan Dubey, Manjaree Pandit and Surender Reddy Salkuti

Energies 2021, 14(19), 6376; https://doi.org/10.3390/en14196376 - 05 Oct 2021

Cited by 11 | Viewed by 1899

Abstract

Due to increasing concern over global warming, the penetration of renewable energy in power systems is increasing day by day. Gencos that traditionally focused only on maximizing their profit in the competitive market are now also focusing on operation with the minimum pollution [...] Read more.

Due to increasing concern over global warming, the penetration of renewable energy in power systems is increasing day by day. Gencos that traditionally focused only on maximizing their profit in the competitive market are now also focusing on operation with the minimum pollution level. The paper proposes a multiobjective model capable of finding a set of trade-off solutions for the joint optimization problem, considering the cost of reserve and curtailment of power from renewable sources. Managing a hybrid power system is a challenging task due to its stochastic nature mixed with the objective function and complex practical constraints associated with it. A novel metaheuristic Equilibrium Optimizer (EO) algorithm incepted in the year 2020 utilizes the concept of control volume and mass balance for finding equilibrium state is proposed here for computing the optimal schedule and impact of renewable energy integration on profit and emission for different optimization objectives. In this paper, EO has shown dominant performance over well-established metaheuristic algorithms such as particle swarm optimizer (PSO) and artificial bee colony (ABC). In addition, EO produces well-distributed Pareto-optimal solutions and the fuzzy min-ranking is used as a decision maker to acquire the best compromise solution. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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19 pages, 6036 KiB

Open AccessArticle

DC Fault Current Analyzing, Limiting, and Clearing in DC Microgrid Clusters

by Navid Bayati, Hamid Reza Baghaee, Mehdi Savaghebi, Amin Hajizadeh, Mohsen N. Soltani and Zhengyu Lin

Energies 2021, 14(19), 6337; https://doi.org/10.3390/en14196337 - 04 Oct 2021

Cited by 11 | Viewed by 2433

Abstract

A new DC fault current limiter (FCL)-based circuit breaker (CB) for DC microgrid (MG) clusters is proposed in this paper. The analytical expressions of the DC fault current of a bidirectional interlink DC/DC converter in the interconnection line of two nearby DC MGs [...] Read more.

A new DC fault current limiter (FCL)-based circuit breaker (CB) for DC microgrid (MG) clusters is proposed in this paper. The analytical expressions of the DC fault current of a bidirectional interlink DC/DC converter in the interconnection line of two nearby DC MGs are analyzed in detail. Meanwhile, a DC fault clearing solution (based on using a DC FCL in series with a DC circuit breaker) is proposed. This structure offers low complexity, cost, and power losses. To assess the performance of the proposed method, time-domain simulation studies are carried out on a test DC MG cluster in a MATLAB/Simulink environment. The results of the proposed analytical expressions are compared with simulation results. The obtained results verify the analytical expression of the fault current and prove the effectiveness of the proposed DC fault current limiting and clearing strategy. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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20 pages, 8476 KiB

Open AccessArticle

Discrimination of Transformer Inrush Currents and Internal Fault Currents Using Extended Kalman Filter Algorithm (EKF)

by Sunil Kumar Gunda and Venkata Samba Sesha Siva Sarma Dhanikonda

Energies 2021, 14(19), 6020; https://doi.org/10.3390/en14196020 - 22 Sep 2021

Cited by 6 | Viewed by 2257

Abstract

The discrimination of inrush currents and internal fault currents in transformers is an important feature of a transformer protection scheme. The harmonic current restrained feature is used in conventional differential relay protection of transformers. A literature survey shows that the discrimination between the [...] Read more.

The discrimination of inrush currents and internal fault currents in transformers is an important feature of a transformer protection scheme. The harmonic current restrained feature is used in conventional differential relay protection of transformers. A literature survey shows that the discrimination between the inrush currents and internal fault currents is still an area that is open to research. In this paper, the classification of internal fault currents and magnetic inrush currents in the transformer is performed by using an extended Kalman filter (EKF) algorithm. When a transformer is energized under normal conditions, the EKF estimates the primary side winding current and, hence, the absolute residual signal (ARS) value is zero. The ARS value will not be equal to zero for internal fault and inrush phenomena conditions; hence, the EKF algorithm will be used for discriminating the internal faults and inrush faults by keeping the threshold level to the ARS value. The simulation results are compared with the theoretical analysis under various conditions. It is also observed that the detection time of internal faults decreases with the severity of the fault. The results of various test cases using the EKF algorithm are presented. This scheme provides fast protection of the transformer for severe faults. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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20 pages, 5627 KiB

Open AccessArticle

Third-Order Sliding Mode Applied to the Direct Field-Oriented Control of the Asynchronous Generator for Variable-Speed Contra-Rotating Wind Turbine Generation Systems

by Habib Benbouhenni and Nicu Bizon

Energies 2021, 14(18), 5877; https://doi.org/10.3390/en14185877 - 17 Sep 2021

Cited by 39 | Viewed by 2341

Abstract

Traditional direct field-oriented control (DFOC) techniques with integral-proportional (PI) controllers have undesirable effects on the power quality and performance of variable speed contra-rotating wind power (CRWP) plants based on asynchronous generators (ASGs). In this work, a commanding technique based on the DFOC technique [...] Read more.

Traditional direct field-oriented control (DFOC) techniques with integral-proportional (PI) controllers have undesirable effects on the power quality and performance of variable speed contra-rotating wind power (CRWP) plants based on asynchronous generators (ASGs). In this work, a commanding technique based on the DFOC technique for ASG is presented on variable speed conditions to minimize the output power ripples and the total harmonic distortion (THD) of the grid current. A new DFOC strategy was designed based on third-order sliding mode (TOSM) control to minimize oscillations and the THD value of the current and active power of the ASG; the designed technique decreases the current THD from ASG and does not impose any additional undulations in different parts of ASG. The designed technique is simply implemented on traditional DFOC techniques in variable speed DRWP systems to ameliorate its effectiveness. Also, the results show that by using the designed TOSM controllers, in addition to regulating the active and reactive powers of the ASG-based variable speed CRWP system, the THD current and active power undulations of the traditional inverters can be minimized simultaneously, and the stator current became more like a sinusoidal form. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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19 pages, 3880 KiB

Open AccessArticle

Demand-Side Management for Improvement of the Power Quality in Smart Homes Using Non-Intrusive Identification of Appliance Usage Patterns with the True Power Factor

by Hari Prasad Devarapalli, Venkata Samba Sesha Siva Sarma Dhanikonda and Sitarama Brahmam Gunturi

Energies 2021, 14(16), 4837; https://doi.org/10.3390/en14164837 - 08 Aug 2021

Cited by 4 | Viewed by 1608

Abstract

The proliferation of low-power consumer electronic appliances (LPCEAs) is on the rise in smart homes in order to save energy. On the flip side, the current harmonics induced due to these LPCEAs pollute low-voltage distribution systems’ (LVDSs’) supplies, leading to a poor power [...] Read more.

The proliferation of low-power consumer electronic appliances (LPCEAs) is on the rise in smart homes in order to save energy. On the flip side, the current harmonics induced due to these LPCEAs pollute low-voltage distribution systems’ (LVDSs’) supplies, leading to a poor power factor (PF). Further, the energy meters in an LVDS do not measure both the total harmonic distortion (THD) of the current and the PF, resulting in inaccurate billing for energy consumption. In addition, this impacts the useful lifetime of LPCEAs. A PF that takes the harmonic distortion into account is called the true power factor (TPF). It is imperative to measure it accurately. This article measures the TPF using a four-term minimal sidelobe cosine-windowed enhanced dual-spectrum line interpolated Fast Fourier Transform (FFT). The proposed method was used to measure the TPF with a National Instruments cRIO-9082 real-time (RT) system, and four different LPCEAs in a smart home were considered. The RT results exhibited that the TPF uniquely identified each usage pattern of the LPCEAs and could use them to improve the TPF by suggesting an alternative usage pattern to the consumer. A positive response behavior on the part of the consumer that is in their interest can improve the power quality in a demand-side management application. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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24 pages, 26251 KiB

Open AccessArticle

Small-Signal Model and Stability Control for Grid-Connected PV Inverter to a Weak Grid

by Antoine Musengimana, Haoyu Li, Xuemei Zheng and Yanxue Yu

Energies 2021, 14(13), 3907; https://doi.org/10.3390/en14133907 - 29 Jun 2021

Cited by 7 | Viewed by 3076

Abstract

This paper presents a small signal stability analysis to assess the stability issues facing PV (photovoltaic) inverters connected to a weak grid. It is revealed that the cause of the transient instabilities, either high-frequency or low-frequency oscillations, is dominated by the outer control [...] Read more.

This paper presents a small signal stability analysis to assess the stability issues facing PV (photovoltaic) inverters connected to a weak grid. It is revealed that the cause of the transient instabilities, either high-frequency or low-frequency oscillations, is dominated by the outer control loops and the grid strength. However, most challenging oscillations are low-frequency oscillations induced by coupling interaction between the outer loop controller and PLL (Phase-Locked Loop) when the inverter is connected to a weak grid. Therefore, the paper proposes a low-frequency damping methodology in order to enhance the high system integration, while maintaining the stability of the system. The control method uses a DC link voltage error to modulate the reference reactive current. The proposed control reduces the low-frequency coupling between the DVC (DC link voltage controller), AVC (AC voltage controller) and PLL (Phase-locked loop). According to this study’s results, the performance capability of the grid-connected PV inverter is improved and flexibility in the outer loop controller design is enhanced. The control strategy proposed in this paper is tested using the PLECS simulation software (Plexim GmbH, Zurich Switzerland) and the results are compared with the conventional method. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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21 pages, 1395 KiB

Open AccessArticle

Short Term Active Power Load Prediction on A 33/11 kV Substation Using Regression Models

by Venkataramana Veeramsetty, Arjun Mohnot, Gaurav Singal and Surender Reddy Salkuti

Energies 2021, 14(11), 2981; https://doi.org/10.3390/en14112981 - 21 May 2021

Cited by 18 | Viewed by 2114

Abstract

Electric power load forecasting is an essential task in the power system restructured environment for successful trading of power in energy exchange and economic operation. In this paper, various regression models have been used to predict the active power load. Model optimization with [...] Read more.

Electric power load forecasting is an essential task in the power system restructured environment for successful trading of power in energy exchange and economic operation. In this paper, various regression models have been used to predict the active power load. Model optimization with dimensionality reduction has been done by observing correlation among original input features. Load data has been collected from a 33/11 kV substation near Kakathiya University in Warangal. The regression models with available load data have been trained and tested using Microsoft Azure services. Based on the results analysis it has been observed that the proposed regression models predict the demand on substation with better accuracy. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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23 pages, 5071 KiB

Open AccessArticle

Coordinated Control Strategy and Validation of Vehicle-to-Grid for Frequency Control

by Yeong Yoo, Yousef Al-Shawesh and Alain Tchagang

Energies 2021, 14(9), 2530; https://doi.org/10.3390/en14092530 - 28 Apr 2021

Cited by 15 | Viewed by 2541

Abstract

The increased penetration of renewable energy sources (RES) and electric vehicles (EVs) is resulting in significant challenges to the stability, reliability, and resiliency of the electrical grid due to the intermittency nature of RES and uncertainty of charging demands of EVs. There is [...] Read more.

The increased penetration of renewable energy sources (RES) and electric vehicles (EVs) is resulting in significant challenges to the stability, reliability, and resiliency of the electrical grid due to the intermittency nature of RES and uncertainty of charging demands of EVs. There is a potential for significant economic returns to use vehicle-to-grid (V2G) technology for peak load reduction and frequency control. To verify the effectiveness of the V2G-based frequency control in a microgrid, modeling and simulations of single- and multi-vehicle-based primary and secondary frequency controls were conducted to utilize the integrated components at the Canadian Centre for Housing Technology (CCHT)-V2G testing facility by using MATLAB/Simulink. A single-vehicle-based model was validated by comparing empirical testing and simulations of primary and secondary frequency controls. The validated conceptual model was then applied for dynamic phasor simulations of multi-vehicle-based frequency control with a proposed coordinated control algorithm for improving frequency stability and facilitating renewables integration with V2G-capable EVs in a microgrid. This proposed model includes a decentralized coordinated control of the state of charge (SOC) and charging schedule for five aggregated EVs with different departure times and SOC management profiles preferred by EV drivers. The simulation results showed that the fleet of 5 EVs in V2B/V2G could effectively reduce frequency deviation in a microgrid. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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18 pages, 5334 KiB

Open AccessArticle

PV String-Level Isolated DC–DC Power Optimizer with Wide Voltage Range

by Hyungjin Kim, Gibum Yu, Jaehoon Kim and Sewan Choi

Energies 2021, 14(7), 1889; https://doi.org/10.3390/en14071889 - 29 Mar 2021

Cited by 2 | Viewed by 2162

Abstract

This paper proposes a photovoltaic (PV) string-level isolated DC–DC power optimizer with wide voltage range. A hybrid control scheme in which pulse frequency modulation (PFM) control and pulse width modulation (PWM) control are combined with a variable switching frequency is employed to regulate [...] Read more.

This paper proposes a photovoltaic (PV) string-level isolated DC–DC power optimizer with wide voltage range. A hybrid control scheme in which pulse frequency modulation (PFM) control and pulse width modulation (PWM) control are combined with a variable switching frequency is employed to regulate the wide PV voltage range. By adjusting the switching frequency in the above region during the PWM control process, the circulating current period can be eliminated and the turn-on period of the bidirectional switch of the dual-bridge LLC (DBLLC) resonant converter is reduced compared to that with a conventional PWM control scheme with a fixed switching frequency, resulting in better switching and conduction loss. Soft start-up control under a no-load condition is proposed to charge the DC-link electrolytic capacitor from 0 V. A laboratory prototype of a 6.25 kW DBLLC resonant converter with a transformer, including integrated resonant inductance, is built and tested in order to verify the performance and theoretical claims. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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21 pages, 11111 KiB

Open AccessArticle

An Optimized and Decentralized Energy Provision System for Smart Cities

by Ayusee Swain, Surender Reddy Salkuti and Kaliprasanna Swain

Energies 2021, 14(5), 1451; https://doi.org/10.3390/en14051451 - 07 Mar 2021

Cited by 19 | Viewed by 2573

Abstract

Energy efficiency and data security of smart grids are one of the major concerns in the context of implementing modern approaches in smart cities. For the intelligent management of energy systems, wireless sensor networks and advanced metering infrastructures have played an essential role [...] Read more.

Energy efficiency and data security of smart grids are one of the major concerns in the context of implementing modern approaches in smart cities. For the intelligent management of energy systems, wireless sensor networks and advanced metering infrastructures have played an essential role in the transformation of traditional cities into smart communities. In this paper, a smart city energy model is proposed in which prosumer communities were built by interconnecting energy self-sufficient households to generate, consume and share clean energy on a decentralized trading platform by integrating blockchain technology with a smart microgrid. The efficiency and stability of the grid network were improved by using several wireless sensor nodes that manage a massive amount of data in the network. However, long communication distances between sensor nodes and the base station can greatly consume the energy of sensors and decrease the network lifespan. Therefore, bio-inspired algorithm approaches were proposed to improve routing by obtaining the shortest path for traversing the entire network and increasing the system performance in terms of the efficient selection of cluster heads, reduced energy consumption, and extended network lifetime. This was carried out by studying the properties and mechanisms of biological systems and applying them in the communication systems in order to obtain the best results for a specific problem. In this comprehensive model, particle swarm optimization and a genetic algorithm are used to search for the optimal solution in any problem space in less processing time. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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16 pages, 6129 KiB

Open AccessArticle

Design and Fabrication of Solar Thermal Energy Storage System Using Potash Alum as a PCM

by Muhammad Suleman Malik, Naveed Iftikhar, Abdul Wadood, Muhammad Omer Khan, Muhammad Usman Asghar, Shahbaz Khan, Tahir Khurshaid, Ki-Chai Kim, Zabdur Rehman and S. Tauqeer ul Islam Rizvi

Energies 2020, 13(23), 6169; https://doi.org/10.3390/en13236169 - 24 Nov 2020

Cited by 14 | Viewed by 3144

Abstract

Renewable energy resources like solar energy, wind energy, hydro energy, photovoltaic etc. are gaining much importance due to the day by day depletion of conventional resources. Owing to the lower efficiencies of renewable energy resources, much attention has been paid to improving them. [...] Read more.

Renewable energy resources like solar energy, wind energy, hydro energy, photovoltaic etc. are gaining much importance due to the day by day depletion of conventional resources. Owing to the lower efficiencies of renewable energy resources, much attention has been paid to improving them. The concept of utilizing phase change materials (PCMs) has attracted wide attention in recent years. This is due to their ability to extract thermal energy when used in collaboration with photovoltaic (PV), thus improving the photoelectric conversion efficiency. In this paper, the objective is to design and fabricate a novel thermal energy storage system using phase change material. An investigation on the characteristics of Potash Alum as a phase change material due to its low cost, easy availability and its usage as an energy storage for the indoor purposes are taken into account. The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantage of high-energy storage density and the isothermal nature of the storage process. In the current study, potash alum was identified as a phase change material combined with renewable energy sources, that can be efficiently and effectively used in storing thermal energy at compartively lower temperatures that can later be used in daily life heating requirements.A parabolic dish which acts of a heat collector is used to track and reflects solar radiation at a single point on a receiver tank. Heat transfer from the solar collector to the storage tank is done by using a circulating heat transfer fluid with the help of a pump. The experimental results show that this system is capable of successfully storing and utilizing thermal energy on indoor scale such as cooking, heating and those applications where temperature is below 92 °C. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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18 pages, 3292 KiB

Open AccessArticle

Robust Decentralized Tracking Voltage Control for Islanded Microgrids by Invariant Ellipsoids

by Hisham M. Soliman, Ehab Bayoumi, Amer Al-Hinai and Mostafa Soliman

Energies 2020, 13(21), 5756; https://doi.org/10.3390/en13215756 - 03 Nov 2020

Cited by 3 | Viewed by 1636

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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32 pages, 5381 KiB

Open AccessReview

Review of Energy Management System Approaches in Microgrids

by Amrutha Raju Battula, Sandeep Vuddanti and Surender Reddy Salkuti

Energies 2021, 14(17), 5459; https://doi.org/10.3390/en14175459 - 02 Sep 2021

Cited by 69 | Viewed by 8085

Abstract

To sustain the complexity of growing demand, the conventional grid (CG) is incorporated with communication technology like advanced metering with sensors, demand response (DR), energy storage systems (ESS), and inclusion of electric vehicles (EV). In order to maintain local area energy balance and [...] Read more.

To sustain the complexity of growing demand, the conventional grid (CG) is incorporated with communication technology like advanced metering with sensors, demand response (DR), energy storage systems (ESS), and inclusion of electric vehicles (EV). In order to maintain local area energy balance and reliability, microgrids (MG) are proposed. Microgrids are low or medium voltage distribution systems with a resilient operation, that control the exchange of power between the main grid, locally distributed generators (DGs), and consumers using intelligent energy management techniques. This paper gives a brief introduction to microgrids, their operations, and further, a review of different energy management approaches. In a microgrid control strategy, an energy management system (EMS) is the key component to maintain the balance between energy resources (CG, DG, ESS, and EVs) and loads available while contributing the profit to utility. This article classifies the methodologies used for EMS based on the structure, control, and technique used. The untapped areas which have scope for investigation are also mentioned. Full article

(This article belongs to the Special Issue Emerging and Advanced Green Energy Technologies for Sustainable and Resilient Future Grid)

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