Citation: Rameshar, V.; Sharma, G.; Bokoro, P.N.; Çelik, E. Frequency Support Studies of a Diesel–Wind Generation System Using Snake Optimizer-Oriented PID with UC and RFB. Energies 2023, 16, 3417. https://doi.org/10.3390/en16083417 Academic Editors: Saeed Sepasi and Quynh Thi Tu Tran Received: 16 March 2023 Revised: 5 April 2023 Accepted: 10 April 2023 Published: 13 April 2023 Copyright: © 2023 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/). energies Article Frequency Support Studies of a Diesel–Wind Generation System Using Snake Optimizer-Oriented PID with UC and RFB Vikash Rameshar 1 , Gulshan Sharma 1, * , Pitshou N. Bokoro 1 and Emre Çelik 2 1 Department of Electrical Engineering Technology, University of Johannesburg, Johannesburg 2006, South Africa; vikashr@uj.ac.za (V.R.); pitshoub@uj.ac.za (P.N.B.) 2 Department of Electrical and Electronics Engineering, Engineering Faculty, Düzce University, Düzce 81620, Turkey; emrecelik@duzce.edu.tr * Correspondence: gulshans@uj.ac.za Abstract: The present paper discusses the modeling and analysis of a diesel–wind generating system capable enough to cater to the electrical power requirements of a small consumer group or society. Due to high variations of the load demand or due to changes in the wind speed, the frequency of the diesel–wind system will be highly disturbed, and hence to regulate the frequency and power deviations of the wind turbine system, an effective controller design is a necessary requirement, and therefore this paper proposes a novel controller design based on PID scheme. The parameters of this controller is effectively optimized through a new snake optimizer (SO) in an offline manner to minimize frequency and power deviations of an isolated diesel–wind system. The performance of SO-PID for the diesel–wind system is evaluated by considering the integral of time multiplied absolute error (ITAE), integral absolute error (IAE), and integral of time multiplied square error (ITSE). The results were calculated for a step change in load, step change in wind speed, load change at different instants of time with diverse magnitude, and for random load patterns, and they were compared with some of the recently published results under similar working conditions. In addition, the effect of an ultracapacitor (UC) and redox flow battery (RFB) on SO-PID was investigated for the considered system, and the application results demonstrated the advantages of our proposal over other studied designs. Keywords: RES; diesel engine generator; wind turbine generator; ultracapacitor; redox flow battery 1. Introduction As a working citizen, every improvement in the public domain stems from enhance- ments made within the industrial sectors, and these changes require massive amounts of energy directly associated with electricity. The demand for electrical power has induced the need for electrical industries to bring out their competitive side. Although competi- tion is encouraged among the industries, the fossil fuel (FF) units that produce the bulk of the electrical energy cannot meet the demand by utilizing only standard steam-based energy generation. This demand for electrical power can only be met by finding new energy-producing methods. One of the global development goals is for renewable en- ergy sources (RESs) which, going into the future, would provide clean essential energy generation and would remove the reliance on fossil fuels [1]. Clean, renewable energy is produced and includes biomass, hydrogen, biofuels, hydro control, sun-powered radiation, wind pressure, geothermal assets, and ocean essentials which RESs have been utilizing. Technology towards sun-radiated, that is, photovoltaic (PV) and wind energy units, have been dominating and increasing due to the neighborhood-specific environments and ad- vancements within the RESs. Additionally, it boosts positive finance and the development of communities [2]. Within these RES structures that promote growth, one has to adhere to the control and importance of the generated power and how it progresses if RESs are to be fully implemented within the energy system. Energies 2023, 16, 3417. https://doi.org/10.3390/en16083417 https://www.mdpi.com/journal/energies