Integration of high voltage AC/DC grids into modern power systems

© 2020 by the author. The Special Issue on Integration of High Voltage AC/DC Grids into Modern Power Systems is published. A total of five qualified papers are published in this Special Issue. The topics of the papers are control, protection, operation, planning, and scheduling of high voltage AC/DC grids. Twenty-five researchers have participated in this Special Issue. We hope that this Special Issue is helpful for high voltage applications

Emerging Challenges in Smart Grid Cybersecurity Enhancement: A Review

In this paper, a brief survey of measurable factors affecting the adoption of cybersecurity enhancement methods in the smart grid is provided. From a practical point of view, it is a key point to determine to what degree the cyber resilience of power systems can be improved using cost-effective resilience enhancement methods. Numerous attempts have been made to the vital resilience of the smart grid against cyber-attacks. The recently proposed cybersecurity methods are considered in this paper, and their accuracies, computational time, and robustness against external factors in detecting and identifying False Data Injection (FDI) attacks are evaluated. There is no all-inclusive solution to fit all power systems requirements. Therefore, the recently proposed cyber-attack detection and identification methods are quantitatively compared and discusse

Power Management and Protection in MT-HVDC Systems with the Integration of High-Voltage Charging Stations

Due to the significant increase of the long-distance electricity demand, effective use of Distributed Generations (DGs) in power system, and the challenges in the expansion of new transmission lines to improve the reliability of power system reliability, utilizing Multi-Terminal HVDC (MT-HVDC) technology is an applicable, reliable, and cost-effective solution in hybrid AC/DC grids. MT-HVDC systems have flexibility in terms of independent active and reactive power flow (reversible control) and voltage control. Interconnecting two AC grids with different frequencies and transmitting electricity for the long-distance with low power-losses, which leads to less operation and maintenance costs, can be done through the MT-HVDC systems. The integration of large-scale remote DGs, e.g., wind farms, solar power plants, etc., and high-voltage charging stations for Electric Vehicles (EVs) into the power grid have different issues, such as economic, technical, and environmental challenges of transmission and network expansion/operation of both AC and DC grids. In details, damping oscillation, voltage support at different buses, operation of grid-connected inverters to the off-shore and on-shore AC systems, integrating of existing converter stations in MT-HVDC systems without major changes in control system, evaluation of communication infrastructure and also reactive power and filtering units’ requirements in MT-HVDC systems are the technical challenges in this technology. Therefore, a reliable MT-HVDC system can be a possible mean of resolving all the above-mentioned issues. MT-HVDC systems need a control system that can bring stability to the power system during a certain period of the operation/planning time while providing effective and robust electricity. This thesis presents an improved droop-based control strategy for the active and reactive power-sharing on the large-scale MT-HVDC systems integrating different types of AC grids considering the operation of the hybrid AC/DC grids under normal/contingency conditions. The main objective of the proposed strategy is to select the best parameters of the local terminal controllers at the site of each converter station (as the primary controller) and a central master controller (supervisory controller) to control the Power Flow (PF) and balance the instantaneous power in MT-HVDC systems. In this work, (1) various control strategies of MT-HVDC systems are investigated to propose (2) an improved droop-based power-sharing strategy of MT-HVDC systems while the loads (e.g., high-voltage charging stations) in power systems have significant changes, to improve the frequency response and accuracy of the PF control, (3) a new topology of a fast proactive Hybrid DC Circuit Breaker (HDCCB) to isolate the DC faults in MT-HVDC grids in case of fault current interruption. The results from this research work would include supporting energy adequacy, increasing renewable energy penetration, and minimizing losses when maintaining system integrity and reliability. The proposed strategies are evaluated on different systems, and various case scenarios are applied to demonstrate their feasibility and robustness. The validation processes are performed using MATLAB software for programming, and PSCAD/EMTDC and MATLAB/Simulink for simulation

Integration of AC/DC microgrids into power grids

© 2020 by the authors. The Special Issue on Integration of AC/DC Microgrids into Power Grids is published. A total of six qualified papers are published in this Special Issue. The topics of the papers are the Optimal Power Flow (OPF), control, protection, and the operation of hybrid AC/DC microgrids. Nine researchers participated in this Special Issue. We hope that this Special Issue is helpful for sustainable energy applications

Introduction of a new and multilateral approach in rapid health impact assessment of development projects: A case study of saman sport-tourism project

Background and purpose: Health Impact Assessment (HIA) evaluates positive and negative consequences of development on human health, which is recently proposed in Iran. Human health involves a wide range of factors, therefore, predicting and estimation of their effects require convenient and efficient tools. Materials and methods: In this case study, data was collected and a database on regional health status was created. The research was then carried out in three main stages, including 1- assessment of the epidemiology of important diseases and health risks, 2- health impact assessment of the project via micro-activities, 3-assessment of impacts on three health components, including physical health, metaphysical health, and socio-economic and cultural factors. After assessing negative and positive effects, scoring was performed based on a multidisciplinary panel of experts. Results: According to the final scores calculated, most concerns were associated with diarrheal diseases, intestinal parasites, conjunctiva, and leishmaniasis. On the other hand, preventing and reducing the likelihood of illness due to lack of awareness and the challenge of new people in the region call for extensive cultural and social planning. Conclusion: Quantitative, accurate, rapid, and reliable results of multilateral approach matrix, were able to predict positive and negative effects, thereby leading to an integrated management solutions to mitigate the negative impacts and improving the quality of the project. Implementation of the project proposed was found to be non-problematic while carrying out corrective actions and authorized health monitoring program. © 2018, Mazandaran University of Medical Sciences. All rights reserved

Optimal placement of TCSC for congestion management and power loss reduction using multi-objective genetic algorithm

© 2020 by the authors. Electricity demand has been growing due to the increase in the world population and higher energy usage per capita as compared to the past. As a result, various methods have been proposed to increase the efficiency of power systems in terms of mitigating congestion and minimizing power losses. Power grids operating limitations result in congestion that specifies the final capacity of the system, which decreases the conventional power capabilities between coverage areas. Flexible AC Transmission Systems (FACTS) can help to decrease flows in heavily loaded lines and lead to lines loadability improvements and cost reduction. In this paper, total power loss reduction and line congestion improvement are assessed by determining the optimal locations and compensation rates of Thyristor-Controlled Series Compensator (TCSC) devices using the Multi-Objective Genetic Algorithm (MOGA). The results of applying the proposed method on the IEEE 30-bus test system confirmed the efficiency of the proposed procedure. In addition, to check the performance, applicability, and effectiveness of the proposed method, different heuristic algorithms, such as the multi-objective Particle Swarm Optimization (PSO) algorithm, Differential Evolution (DE) algorithm, and Mixed-Integer Non-Linear Program (MINLP) technique, are used for comparison. The obtained results show the accuracy and fast convergence of the proposed method over the other heuristic techniques

A comprehensive review on brushless doubly-fed reluctance machine

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. The Brushless Doubly-Fed Reluctance Machine (BDFRM) has been widely investigated in numerous research studies since it is brushless and cageless and there is no winding on the rotor of this emerging machine. This feature leads to several advantages for this machine in comparison with its induction counterpart, i.e., Brushless Doubly-Fed Induction Machine (BDFIM). Less maintenance, less power losses, and also more reliability are the major advantages of BDFRM compared to BDFIM. The design complexity of its reluctance rotor, as well as flux patterns for indirect connection between the two windings mounted on the stator including power winding and control winding, have restricted the development of this machine technology. In the literature, there is not a comprehensive review of the research studies related to BDFRM. In this paper, the previous research studies are reviewed from different points of view, such as operation, design, control, transient model, dynamic model, power factor, Maximum Power Point Tracking (MPPT), and losses. It is revealed that the BDFRM is still evolving since the theoretical results have shown that this machine operates efficiently if it is well-designed

A comprehensive review on brushless doubly-fed reluctance machine

The Brushless Doubly-Fed Reluctance Machine (BDFRM) has been widely investigated in numerous research studies since it is brushless and cageless and there is no winding on the rotor of this emerging machine. This feature leads to several advantages for this machine in comparison with its induction counterpart, i.e., Brushless Doubly-Fed Induction Machine (BDFIM). Less maintenance, less power losses, and also more reliability are the major advantages of BDFRM compared to BDFIM. The design complexity of its reluctance rotor, as well as flux patterns for indirect connection between the two windings mounted on the stator including power winding and control winding, have restricted the development of this machine technology. In the literature, there is not a comprehensive review of the research studies related to BDFRM. In this paper, the previous research studies are reviewed from different points of view, such as operation, design, control, transient model, dynamic model, power factor, Maximum Power Point Tracking (MPPT), and losses. It is revealed that the BDFRM is still evolving since the theoretical results have shown that this machine operates efficiently if it is well-designed

An improved droop-based control strategy for MT-HVDC systems

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This paper presents an improved droop-based control strategy for the active and reactive power-sharing on the large-scale Multi-Terminal High Voltage Direct Current (MT-HVDC) systems. As droop parameters enforce the stability of the DC grid, and allow the MT-HVDC systems to participate in the AC voltage and frequency regulation of the different AC systems interconnected by the DC grids, a communication-free control method to optimally select the droop parameters, consisting of AC voltage-droop, DC voltage-droop, and frequency-droop parameters, is investigated to balance the power in MT-HVDC systems and minimize AC voltage, DC voltage, and frequency deviations. A five-terminal Voltage-Sourced Converter (VSC)-HVDC system is modeled and analyzed in EMTDC/PSCAD and MATLAB software. Different scenarios are investigated to check the performance of the proposed droop-based control strategy. The simulation results show that the proposed droop-based control strategy is capable of sharing the active and reactive power, as well as regulating the AC voltage, DC voltage, and frequency of AC/DC grids in case of sudden changes, without the need for communication infrastructure. The simulation results confirm the robustness and effectiveness of the proposed droop-based control strategy

A bidirectional power charging control strategy for Plug-in Hybrid Electric Vehicles

© 2019 by the authors. Plug-in Hybrid Electric Vehicles (PHEVs) have the potential of providing frequency regulation due to the adjustment of power charging. Based on the stochastic nature of the daily mileage and the arrival and departure time of Electric Vehicles (EVs), a precise bidirectional charging control strategy of plug-in hybrid electric vehicles by considering the State of Charge (SoC) of the batteries and simultaneous voltage and frequency regulation is presented in this paper. The proposed strategy can control the batteries charge which are connected to the grid, and simultaneously regulate the voltage and frequency of the power grid during the charging time based on the available power when different events occur over a 24-h period. The simulation results prove the validity of the proposed control strategy in coordinating plug-in hybrid electric vehicles aggregations and its significant contribution to the peak reduction, as well as power quality improvement. The case study in this paper consists of detailed models of Distributed Energy Resources (DERs), diesel generator and wind farm, a generic aggregation of EVs with various charging profiles, and different loads. The test system is simulated and analyzed in MATLAB/SIMULINK software