Power
Babak Keshavarz Zahed; Mohammad Hassan Moradi
Abstract
The penetration of double-fed induction generators (DFIG) as renewable energy sources (RES) in power systems leads to fluctuations caused by wind energy. Therefore, based on this challenge, a wide area damping controller (WADC) has been designed to compensate the oscillatory modes by a static synchronous ...
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The penetration of double-fed induction generators (DFIG) as renewable energy sources (RES) in power systems leads to fluctuations caused by wind energy. Therefore, based on this challenge, a wide area damping controller (WADC) has been designed to compensate the oscillatory modes by a static synchronous series compensator (SSSC). In addition to the design of WADC for SSSC, a parallel compensator in the form of a supercapacitor energy storage system (SCESS) has been used in the DC link of the wind unit so that DFIG can be used optimally to supply the power system. The design method for compensating time delays in WADC is based on free weight matrices (FWM). First, based on the theory of robust control based on delay-dependent feedback, a set of constraints related to linear matrix inequality (LMI) are formulated. In the following, the free weight matrix (FWM) has been used to solve the delay-dependent time problem. The purpose of applying FWM is to extract the most optimal gain for the controller in the presence of time delay. The proposed FWM matrix tries to find the most optimal gain in the controller with the help of an iterative algorithm based on the linearization of conical complement. The simulation results have been implemented in the MATLAB software environment after obtaining the critical modes in the nonlinear time domain on the power system of 16 improved machines. Based on the simulation results, the robustness of the proposed controller under various uncertainties is clearly shown in this paper.
Power
Ali Morsagh Dezfuli; Mahyar Abasi; Mohammad Esmaeil Hasanzadeh; Mahmood Joorabian
Abstract
The utilization of distributed generation (DG) in today's power systems has led to the emergence of the concept of microgrids, in addition to changing the mode of generating and supplying the energy required for network electrical loads. When a microgrid operates in the island mode, energy generation ...
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The utilization of distributed generation (DG) in today's power systems has led to the emergence of the concept of microgrids, in addition to changing the mode of generating and supplying the energy required for network electrical loads. When a microgrid operates in the island mode, energy generation sources are responsible for controlling the microgrid’s voltage and frequency. As the microgrid frequency is proportional to the amount of power generated by the DG, the microgrid requires a precise power-sharing strategy. Considering that DGs do not usually have stable output power despite the importance of power stability, the present paper addresses the voltage and frequency control of an islanded microgrid by considering the power generation uncertainties caused by disturbances and the varying power output of DGs. Given that the disturbance on the first DG's input current is 0.2 A, which is approximately 2.2% of the steady-state value, a simulation was performed, and it was observed that the maximum voltage variation of each bus in the worst case was 0.59% for the first bus and 0.53% for the second bus, which means that the controller could control the voltage and frequency values within the permissible range. If the controller is not used, the change in the frequency of each bus will be 10 times, and the voltage change will be 5 times as great as that of the case the controller is used.
Power
Sajed Derakhshani Pour; Reza Eslami
Abstract
In the last few years, there has been growing attention to isolated DC microgrids (MGs) with robust voltage control and efficient responding to demand in the face of fluctuating demands and supply amounts. This attention is due to significant voltage mismatches originated ...
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In the last few years, there has been growing attention to isolated DC microgrids (MGs) with robust voltage control and efficient responding to demand in the face of fluctuating demands and supply amounts. This attention is due to significant voltage mismatches originated from the sudden transitions of the load demand and the active power of the supplies such as photovoltaic (PV) systems. To address these goals, a novel nonlinear robust voltage control strategy with a cascaded design consisting of proportional-integral (PI) and sliding mode control (SMC) techniques is developed in this research for the battery energy storage system (BESS). Additionally, this research considers a fuel cell as another power supply in addition to a solar PV system. For maximum power point tracking (MPPT) of the PV system, a novel backstepping sliding mode control (BSMC) technique is developed as well. The effective functioning of the suggested cascaded control strategy is examined using MATLAB/Simulink. The outcomes of the simulation represent the effectiveness of the proposed approach in robustly regulating the voltage level of the DC link at 50 V with small deviations in tracking, and quick reaction to fluctuations in both demand and supply sides, as well as guaranteeing an evenly-distributed responding to demand fluctuations from the DC MG.
Power
Nicholas Kwesi Prah II; Elvis Twumasi; Emmanuel Asuming Frimpong
Abstract
The Combined Economic Emission Dispatch (CEED) is an important consideration in every power system. In this paper, a modified Mayfly Algorithm named Modified Individual Experience Mayfly Algorithm (MIE-MA) is used to solve the CEED optimization problem. The modified algorithm enhances the balance between ...
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The Combined Economic Emission Dispatch (CEED) is an important consideration in every power system. In this paper, a modified Mayfly Algorithm named Modified Individual Experience Mayfly Algorithm (MIE-MA) is used to solve the CEED optimization problem. The modified algorithm enhances the balance between exploration and exploitation by utilizing a chaotic decreasing gravity coefficient. Additionally, instead of the MA relying solely on the best position, it calculates the experience of a mayfly by averaging its positions. The CEED problem is modeled as a nonlinear optimization problem constrained with four equality and inequality constraints and tested on a grid-connected microgrid that consists of four dispatchable distributed generators and two renewable energy sources. The performance of the MIE-MA on the CEED problem is compared to Particle Swarm Optimisation (PSO), an MA variant that incorporates a levy flight algorithm named IMA and Dragonfly Algorithm (DA) using the MATLAB R2021a software. The MIE-MA achieved the best optimum cost of 11306.6 $/MWh, compared to 12278.0 $, 12875.8$, and 17146.4$ of the DA, IMA, and PSO respectively. The MIE-MA also achieved the best average optimum cost over 20 runs of 12163.48 $, compared to 12555.36 $, 13419.67 $, and 17270.08 $ of the DA, IMA, and PSO respectively. The hourly cost curve of the MIE-MA was also the best compared to the other algorithms. The MIE-MA algorithm thus achieves superior optimal values with fewer iterations.
Power
Elvis Twumasi; Yussif Seini Abdul-Fatawu; Emmanuel Asuming Frimpong
Abstract
The optimal size and location of series capacitors is a critical challenge in a distribution network. In this paper, a novel approach for enhancing voltage stability in distribution networks through the optimal sizing and placement of series capacitors is proposed. The study introduces a technique to ...
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The optimal size and location of series capacitors is a critical challenge in a distribution network. In this paper, a novel approach for enhancing voltage stability in distribution networks through the optimal sizing and placement of series capacitors is proposed. The study introduces a technique to determine the optimal lines for connecting series capacitors based on line reactance and current. A modified Elephant Herding Optimization (MEHO) algorithm was used to determine the reactance sizes of the series capacitors and the best lines to place them for optimum system performance. To evaluate the effectiveness of the proposed method, three series capacitors are placed and sized in the standard IEEE 33-bus radial distribution system for stability enhancement. A comparison is conducted between the proposed MEHO algorithm-based approach, the original Elephant Herding Optimization (EHO) algorithm, and the IGWO-TS-based methods reported in the literature. The evaluation is performed by analyzing the system voltage profile, total system losses, and system voltage deviation index under varying loading conditions of 30%, 100%, and 120% of the system nominal loading. Results demonstrate that the proposed MEHO algorithm-based approach outperforms the other two methods significantly in all the scenarios, highlighting its effectiveness in voltage stability enhancement in distribution networks.
Power
Nabil Mezhoud; Mohamed Amarouayache
Abstract
This paper presents a solution to the Optimal Power Flow (OPF) problem combined economic dispatch with valve-point effect and Emission Index (EI) in electrical power networks using the physics-inspired optimization method, which is the Gravitational Search Algorithm (GSA). Our main goal is to minimize ...
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This paper presents a solution to the Optimal Power Flow (OPF) problem combined economic dispatch with valve-point effect and Emission Index (EI) in electrical power networks using the physics-inspired optimization method, which is the Gravitational Search Algorithm (GSA). Our main goal is to minimize the objective function necessary for the best balance between energy production and its consumption which is presented in a nonlinear function, taking into account equality and inequality constraints. The objective is to minimize the total cost of active generations, the active power losses, and the emission index. The GSA method has been examined and tested on the standard IEEE 30-bus test system with various objective functions. The simulation results of the used methods have been compared and validated with those reported in the recent literature. The results are promising and show the effectiveness and robustness of the used method. It should be mentioned that from the base case, the cost generation, the active power losses, and the emission index are significantly reduced to 823 ($/h), 6.038 (MW), and 0.227 (ton/h), which are considered 5.85%, 61.61%, and 44.63%, respectively.
Power
Farhad Amiri; Mohammad Hassan Moradi
Abstract
With the presence of distributed energy resources in the microgrid, the problem of load-frequency control (LFC) becomes one of the most important concerns. With changing the parameters of the microgrid components as well as the disturbances forced to the grid, designing a suitable LFC becomes more difficult. ...
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With the presence of distributed energy resources in the microgrid, the problem of load-frequency control (LFC) becomes one of the most important concerns. With changing the parameters of the microgrid components as well as the disturbances forced to the grid, designing a suitable LFC becomes more difficult. In this paper, the design of a Robust model predictive controller (RMPC) based on the linear matrix inequality as a secondary controller LFC system is discussed for controlling a microgrid on the shipboard. The main purpose of the proposed method is to improve the frequency stability of the microgrid in the presence of disturbances and the uncertainty of its parameters. The proposed controller simulation results, in several different scenarios, considering The uncertainty of the microgrid parameters as well as the input disturbances are compared. The main controllers are the fuzzy proportional-integral type1 and 2, and multi-objective multi-purpose functions optimized with the MOFPI (MBBHA), MOIT2FPI (MBHA) algorithm. The effectiveness of the proposed method in terms of The response speed and reduction of fluctuations and overcome uncertainties of the parameters, as well as robustness to disturbances, are discussed. Simulation is implemented in MATLAB software. The proposed method reduces the frequency oscillations caused by disturbances on the microgrid by 68% (68% improvement over other methods used in this field). Also, using this method, the damping speed of microgrid frequency fluctuations is increased by 53% (performance improvement).