Special Issue "Symmetry in Renewable Energy and Power Systems"

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Computer and Engineer Science and Symmetry".

Deadline for manuscript submissions: closed (30 September 2020).

Special Issue Editors

Dr. Raúl Baños Navarro
Website
Guest Editor
Department of Engineering, Electrical Engineering section, University of Almería, Almería E-04120, Spain
Interests: power systems; renewable energy; engineering economics; network optimization; multi-objective optimization; ICT in education
Special Issues and Collections in MDPI journals
Dr. Alfredo Alcayde
Website
Guest Editor
Department of Engineering, Universidad de Almería; La Cañada de San Urbano s/n; 04120 Almería, Spain
Interests: electrical engineering; power systems; renewable energy; optimization
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

The study of power systems is closely related with symmetry. For example, multiphase power systems are inherently symmetric. The study of symmetrical and asymmetrical faults in power systems is a critical issue. The phase sequence arrangements of multicircuit overhead lines on the same tower directly affects the symmetry of power transmission systems, which influence the operation of power grid and relay protection. Moreover, symmetry is a topic of intensive investigation in the analysis of grid interconnection, including symmetrical and asymmetrical network parameters in smart-grid infrastructures. In renewable energy, the symmetry is present in the layout of wind power plants or photovoltaic plants, among others, while solar systems can have a different performance if they are used with symmetric and asymmetric concentrating CPC collectors.

This Special Issue invites researchers to submit original research papers and review articles related to renewable energy and power systems in which theoretical or practical issues of symmetry are considered. Applied case studies are especially welcome. The topics of interest include but are not limited to:

  • Symmetry in the topology of power grids;
  • Symmetry in multiphase/polyphase power systems. Power network synchronization;
  • Symmetric and asymmetric components;
  • Symmetrical and asymetrical faults in power systems;
  • Symmetry analysis of phase sequence arrangements of multicircuit overhead lines;
  • Symmetry studies of electrical signals using signal processing methods (FFT, DFT, STFT, WT, etc.);
  • Symmetry in power electronics devices and renewable energy components;
  • Symmetry in renewable energy systems (including smart-grids and micro-grids);
  • Symmetrical analysis of power plant layouts and location (including wind farms and photovoltaic plants);
  • Algorithms for studying symmetry in renewable energy and power systems.

Prof. Dr. Raúl Baños
Dr. Alfredo Alcayde
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • symmetry
  • power systems
  • renewable energy systems
  • topology
  • smart-grids

Published Papers (9 papers)

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Research

Open AccessArticle
Second-Order Cone Approximation for Voltage Stability Analysis in Direct-Current Networks
Symmetry 2020, 12(10), 1587; https://doi.org/10.3390/sym12101587 - 24 Sep 2020
Abstract
In this study, the voltage stability margin for direct current (DC) networks in the presence of constant power loads is analyzed using a proposed convex mathematical reformulation. This convex model is developed by employing a second-order cone programming (SOCP) optimization that transforms the [...] Read more.
In this study, the voltage stability margin for direct current (DC) networks in the presence of constant power loads is analyzed using a proposed convex mathematical reformulation. This convex model is developed by employing a second-order cone programming (SOCP) optimization that transforms the non-linear non-convex original formulation by reformulating the power balance constraint. The main advantage of the SOCP model is that the optimal global solution of a problem can be obtained by transforming hyperbolic constraints into norm constraints. Two test systems are considered to validate the proposed SOCP model. Both systems have been reported in specialized literature with 6 and 69 nodes. Three comparative methods are considered: (a) the Newton-Raphson approximation based on the determinants of the Jacobian matrices, (b) semidefinite programming models, and (c) the exact non-linear formulation. All the numerical simulations are conducted using the MATLAB and GAMS software. The effectiveness of the proposed SOCP model in addressing the voltage stability problem in DC grids is verified by comparing the objective function values and processing time. Full article
(This article belongs to the Special Issue Symmetry in Renewable Energy and Power Systems)
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Open AccessArticle
Coordinated Control and Dynamic Optimal Dispatch of Islanded Microgrid System Based on GWO
Symmetry 2020, 12(8), 1366; https://doi.org/10.3390/sym12081366 - 17 Aug 2020
Abstract
As an effective carrier of renewable distributed power sources, such as wind power and photovoltaics, microgrids have attracted increasing attention as the energy crisis becomes more serious. This paper focuses on the symmetry between the dynamic optimal dispatch and the coordinated control of [...] Read more.
As an effective carrier of renewable distributed power sources, such as wind power and photovoltaics, microgrids have attracted increasing attention as the energy crisis becomes more serious. This paper focuses on the symmetry between the dynamic optimal dispatch and the coordinated control of islanded microgrid to determine the optimal system configuration that can reliably meet energy needs. In order to solve energy management problems, operating costs and environmental benefits, a novel methodology that combines dynamic optimal dispatch and Grey Wolf Optimizer (GWO) is developed in this study to obtain the best output of different system components. This is to minimize the total cost of microgrid power generation and reduce pollutant emissions. In addition, a comparison is carried out between GWO and Particle Swarm Optimization (PSO). Moreover, the comparison between system configurations in six different scenarios and the effectiveness of GWO in solving optimization problems are presented. Finally, the simulation results show that GWO is more effective than PSO in determining the optimization parameters and the utilization rate of renewable energy in different scenarios is up to 92.96%. The simulations and experimental results verify the successful performance of the research method proposed in this study. Full article
(This article belongs to the Special Issue Symmetry in Renewable Energy and Power Systems)
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Open AccessArticle
Asymmetric Compensation of Reactive Power Using Thyristor-Controlled Reactors
Symmetry 2020, 12(6), 880; https://doi.org/10.3390/sym12060880 - 27 May 2020
Cited by 1
Abstract
The thyristor-controlled reactor (TCR) compensator for smooth asymmetric compensation of reactive power in a low-voltage utility grid is proposed in this work. Two different topologies of compensator were investigated: topology based on a single-cored three-phase reactor and topology with separate reactors for every [...] Read more.
The thyristor-controlled reactor (TCR) compensator for smooth asymmetric compensation of reactive power in a low-voltage utility grid is proposed in this work. Two different topologies of compensator were investigated: topology based on a single-cored three-phase reactor and topology with separate reactors for every phase. The investigation of the proposed TCR compensator was performed experimentally using a developed experimental test bench for 12 kVAr total reactive power. The obtained results show that employment of separate reactors for every phase allows us to control the reactive power in every phase independently, and that the TCR compensator with three single-phase reactors is suitable for smooth and asymmetric compensation of reactive power in a low-voltage utility grid. Full article
(This article belongs to the Special Issue Symmetry in Renewable Energy and Power Systems)
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Open AccessArticle
Direct Power Compensation in AC Distribution Networks with SCES Systems via PI-PBC Approach
Symmetry 2020, 12(4), 666; https://doi.org/10.3390/sym12040666 - 23 Apr 2020
Cited by 6
Abstract
Here, we explore the possibility of employing proportional-integral passivity-based control (PI-PBC) to support active and reactive power in alternating current (AC) distribution networks by using a supercapacitor energy storage system. A direct power control approach is proposed by taking advantage of the Park’s [...] Read more.
Here, we explore the possibility of employing proportional-integral passivity-based control (PI-PBC) to support active and reactive power in alternating current (AC) distribution networks by using a supercapacitor energy storage system. A direct power control approach is proposed by taking advantage of the Park’s reference frame transform direct and quadrature currents ( i d and i q ) into active and reactive powers (p and q). Based on the open-loop Hamiltonian model of the system, we propose a closed-loop PI-PBC controller that takes advantage of Lyapunov’s stability to design a global tracking controller. Numerical simulations in MATLAB/Simulink demonstrate the efficiency and robustness of the proposed controller, especially for parametric uncertainties. Full article
(This article belongs to the Special Issue Symmetry in Renewable Energy and Power Systems)
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Open AccessArticle
Optimal Location and Sizing of PV Sources in DC Networks for Minimizing Greenhouse Emissions in Diesel Generators
Symmetry 2020, 12(2), 322; https://doi.org/10.3390/sym12020322 - 24 Feb 2020
Cited by 12
Abstract
This paper addresses the problem of the optimal location and sizing of photovoltaic (PV) sources in direct current (DC) electrical networks considering time-varying load and renewable generation curves. To represent this problem, a mixed-integer nonlinear programming (MINLP) model is developed. The main idea [...] Read more.
This paper addresses the problem of the optimal location and sizing of photovoltaic (PV) sources in direct current (DC) electrical networks considering time-varying load and renewable generation curves. To represent this problem, a mixed-integer nonlinear programming (MINLP) model is developed. The main idea of including PV sources in the DC grid is minimizing the total greenhouse emissions produced by diesel generators in isolated areas. An artificial neural network is employed for short-term forecasting to deal with uncertainties in the PV power generation. The general algebraic modeling system (GAMS) package is employed to solve the MINLP model by using the CONOPT solver that works with mixed and integer variables. Numerical results demonstrate important reductions of harmful gas emissions to the atmosphere when PV sources are optimally integrated (size and location) to the DC grid. Full article
(This article belongs to the Special Issue Symmetry in Renewable Energy and Power Systems)
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Open AccessFeature PaperArticle
A Simplified Method to Avoid Shadows at Parabolic-Trough Solar Collectors Facilities
Symmetry 2020, 12(2), 278; https://doi.org/10.3390/sym12020278 - 13 Feb 2020
Cited by 2
Abstract
Renewable energy today is no longer just an affordable alternative, but a requirement for mitigating global environmental problems such as climate change. Among renewable energies, the use of solar energy is one of the most widespread. Concentrating Solar Power (CSP) systems, however, is [...] Read more.
Renewable energy today is no longer just an affordable alternative, but a requirement for mitigating global environmental problems such as climate change. Among renewable energies, the use of solar energy is one of the most widespread. Concentrating Solar Power (CSP) systems, however, is not yet fully widespread despite having demonstrated great efficiency, mainly thanks to parabolic-trough collector (PTC) technology, both on a large scale and on a small scale for heating water in industry. One of the main drawbacks to this energy solution is the large size of the facilities. For this purpose, several models have been developed to avoid shadowing between the PTC lines as much as possible. In this study, the classic shadowing models between the PTC rows are reviewed. One of the major challenges is that they are studied geometrically as a fixed installation, while they are moving facilities, as they have a tracking movement of the sun. In this work, a new model is proposed to avoid shadowing by taking into account the movement of the facilities depending on their latitude. Secondly, the model is tested to an existing facility as a real case study located in southern Spain. The model is applied to the main existing installations in the northern hemisphere, thus showing the usefulness of the model for any PTC installation in the world. The shadow projected by a standard, the PTC (S) has been obtained by means of a polynomial approximation as a function of the latitude (Lat) given by S = 0.001 − Lat2 + 0.0121 − Lat + 10.9 with R2 of 99.8%. Finally, the model has been simplified to obtain in the standard case the shadows in the running time of a PTC facility. Full article
(This article belongs to the Special Issue Symmetry in Renewable Energy and Power Systems)
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Open AccessArticle
Evolutionary Algorithms for Community Detection in Continental-Scale High-Voltage Transmission Grids
Symmetry 2019, 11(12), 1472; https://doi.org/10.3390/sym11121472 - 03 Dec 2019
Cited by 1
Abstract
Symmetry is a key concept in the study of power systems, not only because the admittance and Jacobian matrices used in power flow analysis are symmetrical, but because some previous studies have shown that in some real-world power grids there are complex symmetries. [...] Read more.
Symmetry is a key concept in the study of power systems, not only because the admittance and Jacobian matrices used in power flow analysis are symmetrical, but because some previous studies have shown that in some real-world power grids there are complex symmetries. In order to investigate the topological characteristics of power grids, this paper proposes the use of evolutionary algorithms for community detection using modularity density measures on networks representing supergrids in order to discover densely connected structures. Two evolutionary approaches (generational genetic algorithm, GGA+, and modularity and improved genetic algorithm, MIGA) were applied. The results obtained in two large networks representing supergrids (European grid and North American grid) provide insights on both the structure of the supergrid and the topological differences between different regions. Numerical and graphical results show how these evolutionary approaches clearly outperform to the well-known Louvain modularity method. In particular, the average value of modularity obtained by GGA+ in the European grid was 0.815, while an average of 0.827 was reached in the North American grid. These results outperform those obtained by MIGA and Louvain methods (0.801 and 0.766 in the European grid and 0.813 and 0.798 in the North American grid, respectively). Full article
(This article belongs to the Special Issue Symmetry in Renewable Energy and Power Systems)
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Open AccessArticle
Geometric Algebra in Nonsinusoidal Power Systems: A Case of Study for Passive Compensation
Symmetry 2019, 11(10), 1287; https://doi.org/10.3390/sym11101287 - 14 Oct 2019
Abstract
New-generation power networks, such as microgrids, are being affected by the proliferation of nonlinear electronic systems, resulting in harmonic disturbances both in voltage and current that affect the symmetry of the system. This paper presents a method based on the application of geometric [...] Read more.
New-generation power networks, such as microgrids, are being affected by the proliferation of nonlinear electronic systems, resulting in harmonic disturbances both in voltage and current that affect the symmetry of the system. This paper presents a method based on the application of geometric algebra (GA) to the resolution of power flow in nonsinusoidal single-phase electrical systems for the correct determination of its components to achieve passive compensation of true quadrature current. It is demonstrated that traditional techniques based on the concepts of Budeanu, Fryze or IEEE1459 fail to determine the interaction between voltage and current and therefore, are not suitable for being used as a basis for the compensation of nonactive power components. An example is included that demonstrates the superiority of GA method and is compared to previous work where GA approaches and traditional methods have also been used. Full article
(This article belongs to the Special Issue Symmetry in Renewable Energy and Power Systems)
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Open AccessArticle
A Hybrid Active Filter Using the Backstepping Controller for Harmonic Current Compensation
Symmetry 2019, 11(9), 1161; https://doi.org/10.3390/sym11091161 - 12 Sep 2019
Cited by 1
Abstract
This document presents a new hybrid combination of filters using passive and active elements because of the generalization in the use of non-linear loads that generate harmonics directly affecting the symmetry of energy transmission systems that influence the functioning of the electricity grid [...] Read more.
This document presents a new hybrid combination of filters using passive and active elements because of the generalization in the use of non-linear loads that generate harmonics directly affecting the symmetry of energy transmission systems that influence the functioning of the electricity grid and, consequently, the deterioration of power quality. In this context, active power filters represent one of the best solutions for improving power quality and compensating harmonic currents to get a symmetrical waveform. In addition, given the importance and occupation of the transmission network, it is necessary to control the stability of the system. Traditionally, passive filters were used to improve energy quality, but they have endured problems such as resonance, fixed remuneration, etc. In order to mitigate these problems, a hybrid HAPF active power filter is proposed combining a parallel active filter and a passive filter controlled by a backstepping algorithm strategy. This control strategy is compared with two other methods, namely the classical PI control, and the fuzzy logic control in order to verify the effectiveness and the level of symmetry of the backstepping controller proposed for the HAPF. The proposed backstepping controller inspires the notion of stability in Lyapunov’s sense. This work is carried out to improve the performance of the HAPF by the backstepping command. It perfectly compensates the harmonics according to standards. The results of simulations performed under the Matlab/Simulink environment show the efficiency and robustness of the proposed backstepping controller applied on HAPF, compared to other control methods. The HAPF with the backstepping controller shows a significant decrease in the THD harmonic distortion rate. Full article
(This article belongs to the Special Issue Symmetry in Renewable Energy and Power Systems)
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