Citation: Alcayde, A.; Manzano-Agugliaro, F. Symmetry in Renewable Energy and Power Systems II—Including Wind Energy and Fluid Energy. Symmetry 2022, 14, 1644. https://doi.org/10.3390/ sym14081644 Received: 30 June 2022 Accepted: 5 August 2022 Published: 10 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). symmetry SS Editorial Symmetry in Renewable Energy and Power Systems II—Including Wind Energy and Fluid Energy Alfredo Alcayde * and Francisco Manzano-Agugliaro Department of Engineering, University of Almeria, ceiA3, 04120 Almeria, Spain * Correspondence: aalcayde@ual.es This Special Issue has focused on symmetry in renewable energy and energy systems II—including wind energy and fluid power. Seven research articles have been accepted for publication focusing on the topics related to their main keywords: power-electronic-based power system dynamics; multi-converter infeed power system; small-signal stability, large scale system analysis, network dynamics, self-consumption, cover factor, load shifting, energy storage, wind energy, simulation, green energy, nanogrid, water heater, battery, multiple input power sources, DC distribution system and full-bridge converter, smart grid cybersecurity, GOOSE message security, IEC 62351, intrusion detection, artificial in- telligence, microgrid, optimal scheduling, biogeography-based optimization algorithm, adaptive determination mechanism of migration rate, dynamic migration mechanism, power shifting, interruptible load, convolutional neural network (CNN), energy consump- tion, ensemble deep learning, long short-term memory (LSTM), multilayer perceptron, forecasting accuracy, time-series forecasting, energy consumption, energy forecasting, extra trees regressor, ensemble voting regressor, forecasting accuracy, K neighbors regressor, gradient boosting regressor, light gradient boost machine, and random forest regressor. The first article, “Small-Signal Stability of Multi-Converter Infeed Power Grids with Symmetry” [1], is a collaboration between four researchers from China and Germany whose main affiliations were the State Key Laboratory of Advanced Electromagnetic Engineering and Technology (School of Electrical and Electronic Engineering, Huazhong University of Science) and the Technology and Department of Physics (Humboldt University of Berlin). The main conclusion that can be drawn is that the results of large-scale multi-converter analyses help to understand power-electronic-based power system dynamics, such as renewable energy integration. The second article, “Modelling of Consumption Shares for Small Wind Energy Pro- sumers” [2], is a collaboration between six researchers from Estonia, Canada, and Russia whose affiliations were: the Institute of Technology (Estonian University of Life Sciences), Canmet ENERGY Research Centre (Natural Resources Canada), the Department of Electri- cal Power Engineering and Mechatronics (Tallinn University of Technology), the Depart- ment of Solar Business (Eesti Gaas A), the Institute of Engineering Sciences (Pskov State University), and the Estonian Centre of Industrial Mathematics. This article describes the simulation of energy distribution in an average household where electricity is produced with a small wind generator or purchased from the public electricity grid. The results found that for the configuration of the proposed nanogrid option, the positive results were readily achieved when the expected level of wind generator production was known an hour ahead; then, the cover factor increased from 0.593 to 0.645. The third article, “Soft-Switching Full-Bridge Converter with Multiple-Input Sources for DC Distribution Applications” [3], is a collaboration between two researchers from the Department of Electrical Engineering of the Chang Gung University (Taiwan). This research tries to highlight the advantages of power supply systems using the DC distribution method, which involves an increase in conversion efficiency of about 5–10%, a cost reduction of Symmetry 2022, 14, 1644. https://doi.org/10.3390/sym14081644 https://www.mdpi.com/journal/symmetry