scholarly journals Smart Control Strategies for Primary Frequency Regulation through Electric Vehicles: A Battery Degradation Perspective

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4586 ◽  
Author(s):  
Paolo Scarabaggio ◽  
Raffaele Carli ◽  
Graziana Cavone ◽  
Mariagrazia Dotoli
Keyword(s):  
Electric Vehicles ◽  
Operations Management ◽  
Control Strategies ◽  
Power Grid ◽  
Renewable Energy Sources ◽  
Ancillary Services ◽  
Operating Conditions ◽  
Frequency Regulation ◽  
Grid Model ◽  
Primary Frequency

Nowadays, due to the decreasing use of traditional generators in favor of renewable energy sources, power grids are facing a reduction of system inertia and primary frequency regulation capability. Such an issue is exacerbated by the continuously increasing number of electric vehicles (EVs), which results in enforcing novel approaches in the grid operations management. However, from being an issue, the increase of EVs may turn to be a solution to several power system challenges. In this context, a crucial role is played by the so-called vehicle-to-grid (V2G) mode of operation, which has the potential to provide ancillary services to the power grid, such as peak clipping, load shifting, and frequency regulation. More in detail, EVs have recently started to be effectively used for one of the most traditional frequency regulation approaches: the so-called frequency droop control (FDC). This is a primary frequency regulation, currently obtained by adjusting the active power of generators in the main grid. Because to the decommissioning of traditional power plants, EVs are thus recognized as particularly valuable solutions since they can respond to frequency deviation signals by charging or discharging their batteries. Against this background, we address frequency regulation of a power grid model including loads, traditional generators, and several EVs. The latter independently participate in the grid optimization process providing the grid with ancillary services, namely the FDC. We propose two novel control strategies for the optimal control of the batteries of EVs during the frequency regulation service. On the one hand, the control strategies ensure re-balancing the power and stabilizing the frequency of the main grid. On the other hand, the approaches are able to satisfy different types of needs of EVs during the charging process. Differently from the related literature, where the EVs perspective is generally oriented to achieve the optimal charge level, the proposed approaches aim at minimizing the degradation of battery devices. Finally, the proposed strategies are compared with other state-of-the-art V2G control approaches. The results of numerical experiments using a realistic power grid model show the effectiveness of the proposed strategies under the actual operating conditions.

scholarly journals Modeling Vehicles to Grid as a Source of Distributed Frequency Regulation in Isolated Grids with Significant RES Penetration

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 720 ◽  
Author(s):  
Neofytos Neofytou ◽  
Konstantinos Blazakis ◽  
Yiannis Katsigiannis ◽  
Georgios Stavrakakis
Keyword(s):  
Power Systems ◽  
Electric Vehicles ◽  
Renewable Energy Sources ◽  
Rapid Development ◽  
Frequency Regulation ◽  
Charging Station ◽  
Battery Capacity ◽  
Regulation Services ◽  
Primary Frequency ◽  
The Impact

The rapid development of technology used in electric vehicles, and in particular their penetration in electricity networks, is a major challenge for the area of electric power systems. The utilization of battery capacity of the interconnected vehicles can bring significant benefits to the network via the Vehicle to Grid (V2G) operation. The V2G operation is a process that can provide primary frequency regulation services in the electric network by exploiting the total capacity of a fleet of electric vehicles. In this paper, the impact of the plug-in hybrid electric vehicles (PHEVs) in the primary frequency regulation is studied and the effects PHEVs cause in non-interconnected isolated power systems with significant renewable energy sources (RES) penetration. Also it is taken into consideration the requirements of users for charging their vehicles. The V2G operation can be performed either with fluctuations in charging power of vehicles, or by charging or discharging the battery. So an electric vehicle user can participate in V2G operation either during the loading of the vehicle to the charging station, or by connecting the vehicle in the charging station without any further demands to charge its battery. In this paper, the response of PHEVs with respect to the frequency fluctuations of the network is modeled and simulated. Additionally, by using the PowerWorld Simulator software, simulations of the isolated power system of Cyprus Island, including the current RES penetration are performed in order to demonstrate the effectiveness of V2G operation in its primary frequency regulation.

scholarly journals V2G Strategy for Primary Frequency Control of an Industrial Microgrid Considering the Charging Station Operator

Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 549 ◽  
Author(s):  
Sheeraz Iqbal ◽  
Ai Xin ◽  
Mishkat Ullah Jan ◽  
Salman Salman ◽  
Atta ul Munim Zaki ◽  
...  
Keyword(s):  
Electric Vehicles ◽  
Control Strategies ◽  
Frequency Control ◽  
State Of Charge ◽  
Frequency Regulation ◽  
Vehicle To Grid ◽  
Charging Station ◽  
Primary Frequency ◽  
Primary Frequency Control

Electric vehicles (EVs) have been receiving greater attention as a tool for frequency control due to their fast regulation capability. The proliferation of EVs for primary frequency regulation is hampered by the need to simultaneously maintain industrial microgrids dispatch and EV state of charge levels. The current research aims to examine the operative and dominating role of the charging station operator, along with a vehicle to grid strategy; where, indeterminate tasks are executed in the microgrid without the EVs charging/discharging statistics. The role of the charging station operator in regulation is the assignment of the job inside the primary frequency control capacity of electric vehicles. Real-time rectification of programmed vehicle to grid (V2G) power ensures electric vehicles’ state of charge at the desired levels. The proposed V2G strategy for primary frequency control is validated through the application of a two-area interconnected industrial micro-grid and another microgrids with renewable resources. Regulation specifications are communicated to electric vehicles and charging station operators through an electric vehicle aggregator in the proposed strategy. At the charging station operator, V2G power at the present time is utilized for frequency regulation capacity calculation. Subsequently, the V2G power is dispatched in light of the charging demand and the frequency regulation. Furthermore, V2G control strategies for distribution of regulation requirement to individual EVs are also developed. In summary, the article presents a novel primary frequency control through V2G strategy in an industrial microgrid, involving effective coordination of the charging station operator, EV aggregator, and EV operator.

scholarly journals Robustness Comparison of Synthetic Inertia Strategies for Doubly Fed Induction Generators under Different Operating Conditions

2020 ◽  
Author(s):  
Paulo Andrade Souza ◽  
Renan R. dos Santos ◽  
Manoelito C. N. Filho ◽  
Daniel Barbosa ◽  
Luciano Sales Barros
Keyword(s):  
Wind Energy ◽  
Large Scale ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Operating Conditions ◽  
Wind Condition ◽  
Primary Control ◽  
Parameter Uncertainties ◽  
Doubly Fed ◽  
Frequency Behavior

Due to the increasing penetration of Renewable Energy Sources (RES) such as wind energy in electrical grids, Wind Energy Conversion Systems (WECS) participation in primary control is becoming required including the Doubly Fed Induction Generator (DFIG)-based WECS. High integration of large scale DFIG-based WECS brings new challenges to their primary control support, and more strongly due to the wind condition and grid parameter uncertainties. One of the most used types of control strategy for DFIG-based WECS primary support is the synthetic inertia, however, robustness of these techniques have not been tested. In this work three synthetic inertia control strategies will be tested under different operating conditions of wind speed, frequency and voltage sag. For testing the DFIG-based WECS, it was modeled on ATP including its control systems and the results quantified the controllers robustness on the tested controllers with respect to transient frequency behavior.

Research on the Primary Frequency Regulation of the Large Capacity Thermal Power Units

2014 ◽  
Vol 608-609 ◽  
pp. 915-919 ◽  
Author(s):  
Hong Xia Wu
Keyword(s):  
Power Plant ◽  
Control Method ◽  
Power Grid ◽  
Thermal Power ◽  
Frequency Regulation ◽  
Load Curve ◽  
Large Capacity ◽  
Continuous Increase ◽  
Important Index ◽  
Primary Frequency

Frequency is an important index of power quality, primary frequency regulation is of great significance for maintaining the grid frequency. In recent years, with the expansion of the power grid capacity and the continuous increase of the generator capacity, the large capacity units play a role is becoming more and more important in the primary frequency regulation of power grid. This paper takes ultra supercritical coal-fired units (1000MW) of a power plant of Hubei for example, primary frequency regulation control method, requency offset load curve and so on were studied through relevant test.

scholarly journals Analysis of the Sensitivity of Extended Kalman Filter-Based Inertia Estimation Method to the Assumed Time of Disturbance

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 483 ◽  
Author(s):  
Davide del Giudice ◽  
Samuele Grillo
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Situational Awareness ◽  
Renewable Energy Sources ◽  
Estimation Method ◽  
Electric Power System ◽  
Estimation Methods ◽  
Frequency Regulation ◽  
Time Required ◽  
Primary Frequency

The frequency behavior of an electric power system right after a power imbalance is determined by its inertia constant. The current shift in generation mix towards renewable energy sources is leading to a smaller and more variable inertia, thereby compromising the frequency stability of modern grids. Therefore, real-time inertia estimation methods would be beneficial for grid operators, as their situational awareness would be enhanced. This paper focuses on an inertia estimation method specifically tailored for synchronous generators, based on the extended Kalman filter (EKF). Such a method should be started at the time of disturbance, which must be estimated accurately, otherwise additional errors could be introduced in the inertia estimation process. In this paper, the sensitivity of the EKF-based inertia estimation method to the assumed time of disturbance is analyzed. It is shown that such sensitivity is influenced by the initially assumed inertia constant, the use time of the filter and by the time required for primary frequency regulation to be activated.

Research and Optimization of Thermal Power Unit's Automatic Control Based on Frequency Regulation Ability of Power Grid

2013 ◽  
Vol 330 ◽  
pp. 606-610 ◽  
Author(s):  
Jun Li ◽  
Wei Wei Li
Keyword(s):  
Power Systems ◽  
Automatic Control ◽  
Power Grid ◽  
Thermal Power ◽  
Optimal Operation ◽  
Theory And Practice ◽  
Frequency Regulation ◽  
Frequency Compensation ◽  
The Stability ◽  
Primary Frequency

Wind power and other new energy connected to power grid bring new challenges to optimal operation of power systems. The stability of power grid mainly depends on primary frequency compensation and secondary frequency compensation of thermal power units. By analyzing the theory and practice of DEH and coordinated control system (CCS) of thermal power units, combined with the insufficient of actual primary frequency compensation and automatic power generation control (AGC) strategy response to frequency of accidents, the optimization of primary frequency compensation and AGC of thermal power units automatic control were offered. The practical application results show that the proposed control strategy can effectively control the thermal power units to achieve the stability of power grid frequency.

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