Wind Farms and Flexible Loads Contribution in Automatic Generation Control: An Extensive Review and Simulation

With the increasing integration of wind energy sources into conventional power systems, the demand for reserve power has risen due to associated forecasting errors. Consequently, developing innovative operating strategies for automatic generation control (AGC) has become crucial. These strategies ensure a real-time balance between load and generation while minimizing the reliance on operating reserves from conventional power plant units. Wind farms exhibit a strong interest in participating in AGC operations, especially when AGC is organized into different regulation areas encompassing various generation units. Further, the integration of flexible loads, such as electric vehicles and thermostatically controlled loads, is considered indispensable in modern power systems, which can have the capability to offer ancillary services to the grid through the AGC systems. This study initially presents the fundamental concepts of wind power plants and flexible load units, highlighting their significant contribution to load frequency control (LFC) as an important aspect of AGC. Subsequently, a real-time dynamic dispatch strategy for the AGC model is proposed, integrating reserve power from wind farms and flexible load units. For simulations, a future Pakistan power system model is developed using Dig SILENT Power Factory software (2020 SP3), and the obtained results are presented. The results demonstrate that wind farms and flexible loads can effectively contribute to power-balancing operations. However, given its cost-effectiveness, wind power should be operated at maximum capacity and only be utilized when there is a need to reduce power generation. Additionally, integrating reserves from these sources ensures power system security, reduces dependence on conventional sources, and enhances economic efficiency

Capacity Estimation for Vehicle-to-Grid Frequency Regulation Services with Smart Charging Mechanism

Due to various green initiatives, renewable energy will be massively incorporated into the future smart grid. However, the intermittency of the renewables may result in power imbalance, thus adversely affecting the stability of a power system. Frequency regulation may be used to maintain the power balance at all times. As electric vehicles (EVs) become popular, they may be connected to the grid to form a vehicle-to-grid (V2G) system. An aggregation of EVs can be coordinated to provide frequency regulation services. However, V2G is a dynamic system where the participating EVs come and go independently. Thus it is not easy to estimate the regulation capacities for V2G. In a preliminary study, we modeled an aggregation of EVs with a queueing network, whose structure allows us to estimate the capacities for regulation-up and regulation-down, separately. The estimated capacities from the V2G system can be used for establishing a regulation contract between an aggregator and the grid operator, and facilitating a new business model for V2G. In this paper, we extend our previous development by designing a smart charging mechanism which can adapt to given characteristics of the EVs and make the performance of the actual system follow the analytical model.Comment: 11 pages, Accepted for publication in IEEE Transactions on Smart Gri

Integration of EVs and DGs into the Electric Power System for Grid Modernization

Electric power systems (EPSs) are rapidly becoming more complex. Penetration of distributed generators (DGs) are increasing rapidly. Among them, DG units with intermittent renewables resources, such as solar or wind, are attracting more attention. Moreover, plug in electric vehicles (EVs) are expected to be deployed in large numbers over the next decade. These changes present opportunities as well as challenges for reliable and efficient operation of EPS. Integrating EVs in large scale, would result in over-loading of EPS. Interconnection of DGs could impact adversely on the system operation including power quality and safety of the EPS. However, due to the growing number of EVs in the system, faster charging, shorter battery reaction time, and vehicle-to-grid services, EVs could be attractive sources for system operators (SOs) to improve system reliability while creating opportunity for EV owners to gain monetary benefits. In addition, the potential benefits of DG could be sustained in avoiding or shifting investment in transmission lines and/or transformers, minimizing ohmic losses, and protecting the environment. In this dissertation, potential benefits and challenges of EVs and DGs are explored. For some potential benefits, the dissertation develops systematic frameworks, in order to facilitate integration of EVs and DGs into the EPS. Also for some challenges, the dissertation presents solutions to analyze and overcome related difficulties. To study consequences of integrating EVs, a comprehensive model of EV operation is presented. The model covers different modes of operation and includes impact of battery degradation during the operation. The model is then extended to control a large group of EVs efficiently. Several possible ancillary services which could be offered by EVs, including voltage and frequency regulation services, are discussed. Several systematic frameworks are developed to engage EVs in provision of ancillary services, from economical and technical view points. Simulation results clearly indicate EVs ability to participate in ancillary services and possible revenue stream for EV owners. In terms of DGs, the dissertation addresses a common issue in most of utility companies and that is the risk of unintentional islanding of interconnected DGs. A systematic procedure is presented in this dissertation which can detect any possible operating conditions leading to an unintentional islanding of DGs. The developed procedure can serve utility companies as an analytical tool for any interconnection study, in a timely and costly efficient manner. The procedure is not dependent on the anti-islanding schemes nor DG technologies. Simulation results of different real case studies prove the generality and practicality of the procedure

A chronological literature review of electric vehicle interactions with power distribution systems

In the last decade, the deployment of electric vehicles (EVs) has been largely promoted. This development has increased challenges in the power systems in the context of planning and operation due to the massive amount of recharge needed for EVs. Furthermore, EVs may also offer new opportunities and can be used to support the grid to provide auxiliary services. In this regard, and considering the research around EVs and power grids, this paper presents a chronological background review of EVs and their interactions with power systems, particularly electric distribution networks, considering publications from the IEEE Xplore database. The review is extended from 1973 to 2019 and is developed via systematic classification using key categories that describe the types of interactions between EVs and power grids. These interactions are in the framework of the power quality, study of scenarios, electricity markets, demand response, demand management, power system stability, Vehicle-to-Grid (V2G) concept, and optimal location of battery swap and charging stations.Introduction General Overview Chronological Review: Part I Chronological Review: Part II Brief Observations Conclusions and Future Works Final Reflections Author Contributions Funding Acknowledgments Conflicts of Interest Reference

Impact of vehicle to grid in the power system dynamic behaviour

This work was supported in part by FCT-Fundação para a Ciência e a Tecnologia de Portugal, under the grant SFRH/BD/47973/2008 and within the framework of the Project "Green Island" with the Reference MIT-PT/SES-GI/0008/2008, by the European Commission within the framework of the European Project MERGE - Mobile Energy Resources in Grids of Electricity, contract nr. 241399 (FP7) and by INESC Porto - Instituto de Engenharia de Sistemas e Computadores do PortoTese de doutoramento. Sistemas Sustentáveis de Energia. Universidade do Porto. Faculdade de Engenharia. 201