scholarly journals Electric Vehicle Ultra-Fast Battery Chargers: A Boost for Power System Stability?

2021 ◽  
Vol 12 (1) ◽  
pp. 16
Author(s):  
Fabio Mandrile ◽  
Davide Cittanti ◽  
Vincenzo Mallemaci ◽  
Radu Bojoi
Keyword(s):  
Power System ◽  
Electric Vehicle ◽  
Reactive Power ◽  
Short Circuit ◽  
Electric Power System ◽  
System Stability ◽  
High Peak Power ◽  
Charging Station ◽  
Fast Charging ◽  
The Impact

As a consequence of the exponential growth of the electric vehicle (EV) market, DC fast-charging infrastructure is being rapidly deployed all around the world. Ultra-fast charging (UFC) stations are starting to pose serious challenges to the electric power system operation, mostly due to their high peak power demand and unregulated discontinuous operation. To address these issues, local energy storage can be installed, ensuring a smoother grid power absorption profile and allowing to provide grid-supporting features. In this work, a control solution for the grid-side AC/DC converter of next-generation EV UFC stations is proposed. A virtual synchronous compensator (VSC) control algorithm is implemented, in order to lessen the impact of the charging station on the utility and to provide the full spectrum of grid ancillary services (i.e., frequency regulation, reactive power compensation, harmonic reduction, short circuit current generation, etc.). The proposed control strategy is verified experimentally on a downscaled 15 kVA three-phase inverter, emulating the grid front-end of the charging station.

scholarly journals Assessment of the Impact of Geomagnetic Disturbances on Korean Electric Power Systems

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1920 ◽  
Author(s):  
Byoung-Soo Joo ◽  
Jung-Wook Woo ◽  
Jeong-Hun Lee ◽  
Injoo Jeong ◽  
Jungmin Ha ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Reactive Power ◽  
Electric Power Systems ◽  
Geomagnetic Disturbance ◽  
Electric Power System ◽  
System Stability ◽  
Geomagnetic Disturbances ◽  
The Impact

Geomagnetic disturbances have the potential to impact the operation of electric power systems, and thus the assessment of their impacts is required as the first step for secure power system operations. While the effects of the disturbances have been observed primarily at higher latitudes, geomagnetic problems are also observed at mid and low latitude locations, in particular including neighboring countries to Korea such as China and Japan. This paper deals with the assessment of impact of geomagnetic disturbances on Korean electric power systems. For the assessment, the geoelectric fields induced by the geomagnetic disturbances are calculated using geomagnetic data measured over the past 20 years in order to quantify the strength of geomagnetic events in Korea. Then, the geomagnetic currents on the grid driven by the geoelectric fields are computed. Finally, the increased reactive power absorption in high voltage transformers is analyzed and accordingly the change of system voltage magnitudes is identified to evaluate whether the system maintains the voltage stability. The systematic study concludes that during a strong geomagnetic disturbance, the Korean electric power system satisfies the associated standards in the U.S. and maintains system stability.

scholarly journals Unidirectional DC/DC Converter with Voltage Inverter for Fast Charging of Electric Vehicle Batteries

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4791
Author(s):  
Jerzy Ryszard Szymanski ◽  
Marta Zurek-Mortka ◽  
Daniel Wojciechowski ◽  
Nikolai Poliakov
Keyword(s):  
Renewable Energy ◽  
Power System ◽  
Electric Vehicle ◽  
Energy Demand ◽  
Renewable Energy Sources ◽  
Dc Microgrid ◽  
Frequency Converters ◽  
Charging Station ◽  
Fast Charging ◽  
Variable Speed Motor

The paper proposes the adaptation of the industrial plant’s power network to supply electric vehicle (EV) fast-charging converters (above 300 kW) using renewable energy sources (RESs). A 600 V DC microgrid was used to supply energy from RESs for the needs of variable speed motor drives and charging of EV batteries. It has been shown that it is possible to support the supply of drive voltage frequency converters (VFCs) and charging of EV batteries converters with renewable energy from a 600 V DC microgrid, which improves the power quality indicators in the power system. The possibility of implementing the fast EV batteries charging station to the industrial plant’s power system in such a way that the system energy demand is not increased has also been shown. The EV battery charging station using the drive converter has been presented, as well as the results of simulation and laboratory tests of the proposed solution.

scholarly journals Load Flow Analysis in Hybrid AC-DC Transmission Network

2021 ◽  
pp. 617-624
Author(s):  
Ajith M ◽  
Dr. R. Rajeswari
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Power Flow ◽  
Reactive Power ◽  
Short Circuit ◽  
Flow Analysis ◽  
Load Flow ◽  
System Stability ◽  
And Control

Power-flow studies are of great significance in planning and designing the future expansion of power systems as well as in determining the best operation of existing systems. Technologies such as renewables and power electronics are aiding in power conversion and control, thus making the power system massive, complex, and dynamic. HVDC is being preferred due to limitations in HVAC such as reactive power loss, stability, current carrying capacity, operation and control. The HVDC system is being used for bulk power transmission over long distances with minimum losses using overhead transmission lines or submarine cable crossings. Recent years have witnessed an unprecedented growth in the number of the HVDC projects. Due to the vast size and inaccessibility of transmission systems, real time testing can prove to be difficult. Thus analyzing power system stability through computer modeling and simulation proves to be a viable solution in this case. The motivation of this project is to construct and analyze the load flow and short circuit behavior in an IEEE 14 bus power system with DC link using MATLAB software. This involves determining the parameters for converter transformer, rectifier, inverter and DC cable for modelling the DC link. The line chosen for incorporation of DC link is a weak bus. This project gives the results of load flow and along with comparison of reactive power flow, system losses, voltage in an AC and an AC-DC system.

scholarly journals Evaluation of the Effect of Static Load Characteristics on the Level of Frequency during Separate Operations with the Grid

2020 ◽  
Vol 20 (4) ◽  
pp. 54-63
Keyword(s):  
Power System ◽  
Electric Power ◽  
Static Load ◽  
Short Circuit ◽  
Electric Power System ◽  
Static Characteristics ◽  
Steady State Mode ◽  
Load Characteristics ◽  
The Impact ◽  
Circuit Power

ue to the requirements for the quality of electrical energy becoming stricter, it is now relevant to assess the impact of various factors on the main quality indicators: voltage and frequency deviations of the network. One of these factors is the static characteristics of various loads, which under certain conditions can have a significant impact on the parameters of the power system. In this article, it is proposed to evaluate the influence of static characteristics on the network’s frequency level when it enters separate operation with the power system and with various changes in the steady-state mode, and also to investigate the relationship between the coef­ficients of the load regulating effect and the value of the short-circuit power or the length of the supply cable. Separate operation was considered because in this mode, the influence of the regulating effect of a powerful load on the mode parameters becomes more pronounced. The scientific novelty of this study consists in an algorithm that allows refining the frequency deviation of an isolated electric power system, taking into account and without taking into account the static load characteristics when changing the length of the supply cable in the KATRAN software package. The main result of this study is the almost direct relationship revealed between the influence of static load characteristics on the network frequency and the distance of the load with a large proportion of synchronous motors from the power source in an autonomous electric power system. We also evaluated the feasibility of taking the regulatory effect of the load into account when calculating electrical modes depending on the type of load and the calculated value of the short-circuit power.

Time-Domain Simulation of Power System Frequency Fluctuations Caused by Intermittent Wind Power

2013 ◽  
Vol 441 ◽  
pp. 304-311
Author(s):  
Hao Ming Liu ◽  
Fang Fang Zhu ◽  
Ke Lin Yang
Keyword(s):  
Power System ◽  
Wind Power ◽  
Wind Turbines ◽  
Time Domain ◽  
Electric Power System ◽  
System Stability ◽  
Equivalent Transformation ◽  
Time Domain Simulation ◽  
System Frequency ◽  
The Impact

Wind power is uncertain. When the proportion of wind power capacity is large, the impact of the randomness of the output power on the grid frequency is more significant. Aiming at system stability influence after integrating a high capacity of wind turbines, this paper introduces the dynamic simulation model for electric power system with wind power, and makes an equivalent transformation processing for the wind turbine and generator. By using improved Euler method, this paper analyzes the impact of system frequency through time-domain simulation when disturbance occurs at wind farm side. Simulation results show that when wind speed changes, the established model and algorithm can effectively simulate the dynamic response of the frequency, and also these results can provide a reference for the frequency stability when wind turbines integrate into power system.

scholarly journals Power System Stability with Power-Electronic Converter Interfaced Renewable Power Generation: Present Issues and Future Trends

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3441 ◽  
Author(s):  
Lasantha Meegahapola ◽  
Alfeu Sguarezi ◽  
Jack Stanley Bryant ◽  
Mingchen Gu ◽  
Eliomar R. Conde D. ◽  
...  
Keyword(s):  
Power System ◽  
Reactive Power ◽  
Short Circuit ◽  
Power System Stability ◽  
Power Grids ◽  
System Stability ◽  
Power Networks ◽  
Angle Stability ◽  
Rotor Angle Stability ◽  
Stability Issues

The energy sector is currently undergoing a rapid transformation with the integration of power electronic converter (PEC)-interfaced renewable energy sources (RES), such as wind and solar photovoltaic (PV) systems, at both the transmission and distribution networks. Power system stability has been significantly influenced by this power grid transformation. This paper comprehensively reviews major power system stability issues affected due to large-scale integration of PEC-interfaced RES in power grids, with some example case studies relevant for each stability category. According to the review, stability issues are mainly originating from reduction in synchronous inertia, reduction in reactive power reserve, low short-circuit strength of the power network, and fault ride-through (FRT) strategy/capability of the PEC-interfaced RES. Decrease in synchronous inertia could affect both the rotor angle stability and the frequency stability, while decrease in short-circuit strength and reactive power reserve could cause voltage stability and rotor angle stability issues in power networks. Sub-synchronous control interactions are also receiving a lot of attention by the power industry due to increasing oscillatory stability incidents reported in power networks with PEC-interfaced RES. FRT capabilities/strategies of PEC-interfaced RES are also playing a pivotal role in power grid stability due to its influence on active and reactive power, hence more emphasis should be placed on FRT schemes of PEC-interfaced RES, since future power grids are expected to operate with 100% PEC-interfaced generation sources. Stability improvement strategies could be implemented to address multiple stability issues in PEC-interfaced power networks; however, rigorous stability studies are required to identify the optimal conditions to implement these improvement strategies. Furthermore, ongoing structural changes in power grids to accommodate remotely sited PEC-interfaced RES are also influencing the stability of power grids. Therefore, all these factors must be carefully considered by system operators when planning and operating power grids in a secure and stable manner with high penetration levels of PEC-interfaced RES.

scholarly journals Partial Power Processing Based Converter for Electric Vehicle Fast Charging Stations

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 260
Author(s):  
Jon Anzola ◽  
Iosu Aizpuru ◽  
Asier Arruti
Keyword(s):  
Electric Vehicle ◽  
Power Converters ◽  
Power Ratio ◽  
Charging Station ◽  
Fast Charging ◽  
Full Power ◽  
Processing Architectures ◽  
Charging Stations ◽  
Fast Charging Station ◽  
Partial Power Processing

This paper focuses on the design of a charging unit for an electric vehicle fast charging station. With this purpose, in first place, different solutions that exist for fast charging stations are described through a brief introduction. Then, partial power processing architectures are introduced and proposed as attractive strategies to improve the performance of this type of applications. Furthermore, through a series of simulations, it is observed that partial power processing based converters obtain reduced processed power ratio and efficiency results compared to conventional full power converters. So, with the aim of verifying the conclusions obtained through the simulations, two downscaled prototypes are assembled and tested. Finally, it is concluded that, in case galvanic isolation is not required for the charging unit converter, partial power converters are smaller and more efficient alternatives than conventional full power converters.

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