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The sub-aggregation of electric vehicles provides significant potential to power systems in the form of ancillary services. This means with smart charging it is possible to shift loads from peak to off-peak hours. For the flexibility from privately owned electric vehicles to be offered to the electricity market, customer participation is crucial; however, the impacts of sub-aggregation on customers have not been studied thoroughly. In this paper, charging data covering over 80,000 real-world charging sessions from various commercial charging sites are introduced and the charging characteristics are analyzed. Importantly, a method for finding an optimal pattern for load reduction with the least impact on customers is presented. We suggest an optimal schedule for load reduction from the customer viewpoint at different types of charging sites, including public car parks, offices, residential sites, and shopping centers. The findings indicate that residential and office charging sites offer the greatest potential for load reduction with the least impact on customers. The most flexibility is available during peak charging hours, which on average are at 08:00 at car parks, 07:30 at office sites, 19:00 at residential sites, and 10:00 at shopping centers.
Kalle Rauma; Alexander Funke; Toni Simolin; Pertti Järventausta; Christian Rehtanz. Electric Vehicles as a Flexibility Provider: Optimal Charging Schedules to Improve the Quality of Charging Service. Electricity 2021, 2, 225 -243.
AMA StyleKalle Rauma, Alexander Funke, Toni Simolin, Pertti Järventausta, Christian Rehtanz. Electric Vehicles as a Flexibility Provider: Optimal Charging Schedules to Improve the Quality of Charging Service. Electricity. 2021; 2 (3):225-243.
Chicago/Turabian StyleKalle Rauma; Alexander Funke; Toni Simolin; Pertti Järventausta; Christian Rehtanz. 2021. "Electric Vehicles as a Flexibility Provider: Optimal Charging Schedules to Improve the Quality of Charging Service." Electricity 2, no. 3: 225-243.
This study assesses the performance of a multivariate multi-step charging load prediction approach based on the long short-term memory (LSTM) and commercial charging data. The major contribution of this study is to provide a comparison of load prediction between various types of charging sites. Real charging data from shopping centres, residential, public, and workplace charging sites are gathered. Altogether, the data consists of 50,504 charging events measured at 37 different charging sites in Finland between January 2019 and January 2020. A forecast of the aggregated charging load is performed in 15-min resolution for each type of charging site. The second contribution of the work is the extended short-term forecast horizon. A multi-step prediction of either four (i.e., one hour) or 96 (i.e., 24 h) time steps is carried out, enabling a comparison of both horizons. The findings reveal that all charging sites exhibit distinct charging characteristics, which affects the forecasting accuracy and suggests a differentiated analysis of the different charging categories. Furthermore, the results indicate that the forecasting accuracy strongly correlates with the forecast horizon. The 4-time step prediction yields considerably superior results compared with the 96-time step forecast.
Tim Unterluggauer; Kalle Rauma; Pertti Järventausta; Christian Rehtanz. Short‐term load forecasting at electric vehicle charging sites using a multivariate multi‐step long short‐term memory: A case study from Finland. IET Electrical Systems in Transportation 2021, 1 .
AMA StyleTim Unterluggauer, Kalle Rauma, Pertti Järventausta, Christian Rehtanz. Short‐term load forecasting at electric vehicle charging sites using a multivariate multi‐step long short‐term memory: A case study from Finland. IET Electrical Systems in Transportation. 2021; ():1.
Chicago/Turabian StyleTim Unterluggauer; Kalle Rauma; Pertti Järventausta; Christian Rehtanz. 2021. "Short‐term load forecasting at electric vehicle charging sites using a multivariate multi‐step long short‐term memory: A case study from Finland." IET Electrical Systems in Transportation , no. : 1.
There is a general interest from manufacturers, users, regulation institutions, and research around electric vehicles development and its relation with the grid infrastructure. The penetration of electric vehicle in distribution networks brings considerable challenges in terms of power quality, particularly harmonic emissions. Such challenges are more evident in scenarios with high penetration of electric vehicles which consider the clustering effect in the charging process. Methodologies such as Hosting Capacity model electric vehicles as a constant power load with constant harmonic distortion along the entire charging process. This article presents the relationship between the charging algorithms of the electric vehicle chargers, the state of charge of the batteries, and the harmonic current distortion generated during the charging process. This model proposes that the harmonic current distortion depends on the state of charge of the battery and the charging algorithm of the vehicle. As this study would change meaningfully the current studies of power quality related to electric vehicles, practical measurements in two charging stations and offline simulations of the identified onboard chargers are shown to support the content of this paper.
Luis Manuel Caro; Gustavo Ramos; Kalle Rauma; David Felipe Celeita Rodriguez; Davis Montenegro Martinez; Christian Rehtanz. State of Charge Influence on the Harmonic Distortion From Electric Vehicle Charging. IEEE Transactions on Industry Applications 2021, 57, 2077 -2088.
AMA StyleLuis Manuel Caro, Gustavo Ramos, Kalle Rauma, David Felipe Celeita Rodriguez, Davis Montenegro Martinez, Christian Rehtanz. State of Charge Influence on the Harmonic Distortion From Electric Vehicle Charging. IEEE Transactions on Industry Applications. 2021; 57 (3):2077-2088.
Chicago/Turabian StyleLuis Manuel Caro; Gustavo Ramos; Kalle Rauma; David Felipe Celeita Rodriguez; Davis Montenegro Martinez; Christian Rehtanz. 2021. "State of Charge Influence on the Harmonic Distortion From Electric Vehicle Charging." IEEE Transactions on Industry Applications 57, no. 3: 2077-2088.
The number of electric vehicle (EV) users is strongly increasing so that today roughly every second registered vehicle in Norway is an EV. To increase the EV utilization, politics, industry and the EV users strongly promote the integration of fast charging infrastructure. While the future demand of fast charging sites is a well‐studied topic, not much is known about the utilization of the existing charging sites and daily load curves. To fill this knowledge gap, usage data of a charging site in Oslo is analysed. Further on, the impact of a battery energy storage (BES) as well as a photovoltaic generator on peak load reduction is studied. The analysis shows variations and trends in the daily and weekly charging behaviour depending on the degree of utilization of the charging station. On average, a single EV user charges around 10 kWh in 19 min. Furthermore, the evidence indicates that EV users may have adapted fast charging as a part of their daily travels and it is not used only during long distance journeys. The results suggest that a BES can reduce the peak load by up to 55%. By adding a photovoltaic generator, a minor additional reduction of peak load is seen.
Antti Rautiainen; Kalle Rauma; Lena Rohde; Antti Supponen; Fabian Raulf; Christian Rehtanz; Pertti Järventausta. Anatomy of electric vehicle fast charging: Peak shaving through a battery energy storage—A case study from Oslo. IET Electrical Systems in Transportation 2020, 11, 69 -80.
AMA StyleAntti Rautiainen, Kalle Rauma, Lena Rohde, Antti Supponen, Fabian Raulf, Christian Rehtanz, Pertti Järventausta. Anatomy of electric vehicle fast charging: Peak shaving through a battery energy storage—A case study from Oslo. IET Electrical Systems in Transportation. 2020; 11 (1):69-80.
Chicago/Turabian StyleAntti Rautiainen; Kalle Rauma; Lena Rohde; Antti Supponen; Fabian Raulf; Christian Rehtanz; Pertti Järventausta. 2020. "Anatomy of electric vehicle fast charging: Peak shaving through a battery energy storage—A case study from Oslo." IET Electrical Systems in Transportation 11, no. 1: 69-80.
This study presents a practical control method for electric vehicle (EV) charging optimisation for detached and attached houses. The developed EV charging control method utilises real-time measurements to minimise charging costs of up to two EVs in a single household. Since some Finnish distribution system operators have already launched peak power-based distribution tariffs for small-scale customers and because there is a lot of discussion on this kind of tariff development, the control method considers peak power-based charges. Additionally, the proposed smart charging control method utilises charging current measurements as feedback to reallocate unused charging capacity if an EV does not utilise the whole capacity allocated for it. The control method is implemented and tested with commercial EVs. The conducted hardware-in-the-loop simulations and measurements confirm that the control method works as intended. The proposed smart charging control reduces EV charging electricity distribution costs around 60% when compared to the uncontrolled EV charging.
Toni Simolin; Kalle Rauma; Pertti Järventausta; Antti Rautiainen. Optimised controlled charging of electric vehicles under peak power‐based electricity pricing. IET Smart Grid 2020, 3, 751 -759.
AMA StyleToni Simolin, Kalle Rauma, Pertti Järventausta, Antti Rautiainen. Optimised controlled charging of electric vehicles under peak power‐based electricity pricing. IET Smart Grid. 2020; 3 (6):751-759.
Chicago/Turabian StyleToni Simolin; Kalle Rauma; Pertti Järventausta; Antti Rautiainen. 2020. "Optimised controlled charging of electric vehicles under peak power‐based electricity pricing." IET Smart Grid 3, no. 6: 751-759.
The global proliferation of plug-in electric vehicles (PEVs) poses a major challenge for current and future distribution systems. If uncoordinated, their charging process may cause congestion on both network transformers and feeders, resulting in overheating, deterioration, protection triggering and eventual risk of failure, seriously compromising the stability and reliability of the grid. To mitigate such impacts and increase their hosting capacity in radial distribution systems, the present study compares the levels of effectiveness and performances of three alternative centralized thermal management formulations for a real-time agent-based charge control algorithm that aims to minimize the total impact upon car owners. A linear formulation and a convex formulation of the optimization problem are presented and solved respectively by means of integer linear programming and a genetic algorithm. The obtained results are then compared, in terms of their total impact on the end-users and overall performance, with those of the current heuristic implementation of the algorithm. All implementations were tested using a simulation environment considering multiple vehicle penetration and base load levels, and equipment modeled after commercially available charging stations and vehicles. Results show how faster resolution times are achieved by the heuristic implementation, but no significant differences between formulations exist in terms of network management and end-user impact. Every vehicle reached its maximum charge level while all thermal impacts were mitigated for all considered scenarios. The most demanding scenario showcased over a 30% reduction in the peak load for all thermal variants.
César García Veloso; Kalle Rauma; Julián Fernández; Christian Rehtanz. Real-Time Control of Plug-in Electric Vehicles for Congestion Management of Radial LV Networks: A Comparison of Implementations. Energies 2020, 13, 4227 .
AMA StyleCésar García Veloso, Kalle Rauma, Julián Fernández, Christian Rehtanz. Real-Time Control of Plug-in Electric Vehicles for Congestion Management of Radial LV Networks: A Comparison of Implementations. Energies. 2020; 13 (16):4227.
Chicago/Turabian StyleCésar García Veloso; Kalle Rauma; Julián Fernández; Christian Rehtanz. 2020. "Real-Time Control of Plug-in Electric Vehicles for Congestion Management of Radial LV Networks: A Comparison of Implementations." Energies 13, no. 16: 4227.
An increasing share of electric vehicles can mean excessive peak loads in low-voltage power distribution networks. Introducing peak shaving mechanisms to the charging systems, such overloads can be mitigated significantly. The first contribution of this study is to quantify the amount of flexibility that electric vehicles can contribute to peak load reduction so that the drivers can still fully charge the batteries of their vehicles. The second contribution is that the study presents and compares two optimisation strategies for peak load reduction. The work is based on real charging data covering about 25,000 charging sessions at various charging sites in the metropolitan area of the Finnish capital city. The main finding is that the peak loads at charging sites can be reduced by up to 55%. Another important result is that load reduction through low-power charging is achievable only if the average parking time at the charging site is >3 h, without affecting the user experience negatively. It is also found out that the average parking time is over 2 h longer than the average charging time, which indicates the enormous potential of electric vehicles in peak shaving.
Pascal Fenner; Kalle Rauma; Antti Rautiainen; Antti Supponen; Christian Rehtanz; Pertti Järventausta. Quantification of peak shaving capacity in electric vehicle charging – findings from case studies in Helsinki Region. IET Smart Grid 2020, 3, 777 -785.
AMA StylePascal Fenner, Kalle Rauma, Antti Rautiainen, Antti Supponen, Christian Rehtanz, Pertti Järventausta. Quantification of peak shaving capacity in electric vehicle charging – findings from case studies in Helsinki Region. IET Smart Grid. 2020; 3 (6):777-785.
Chicago/Turabian StylePascal Fenner; Kalle Rauma; Antti Rautiainen; Antti Supponen; Christian Rehtanz; Pertti Järventausta. 2020. "Quantification of peak shaving capacity in electric vehicle charging – findings from case studies in Helsinki Region." IET Smart Grid 3, no. 6: 777-785.
Ensuring a stable and reliable operation of current and future distribution networks represents a major challenge for system operators aggravated by the global proliferation of plug-in electric vehicles (PEVs). While the introduction of a controlled charging process would be advantageous to minimise the impacts PEVs cause in the system, a suitable, efficient and ready to be implemented solution is still missing. The present work addresses this issue by proposing a smart charging management solution capable to simultaneously combat the main network impacts derived from the energy needs of the vehicles. This is done by means of an agent-based hierarchical real-time algorithm which combines a local decentralised nodal voltage management with a centralised thermal control conceived to minimise the impact upon participating users. The effectiveness of the proposed system is tested both using a simulation environment considering multiple PEV penetration levels and employing commercially available charging stations and cars through hardware-in-the-loop simulations. The results reveal how all network violations are successfully attenuated by peak shaving the total aggregated charging demand and ensuring a correct system operation for all penetration scenarios while inflicting no impact on the participating users.
César García Veloso; Kalle Rauma; Julián Fernández Orjuela; Christian Rehtanz. Real‐time agent‐based control of plug‐in electric vehicles for voltage and thermal management of LV networks: formulation and HIL validation. IET Generation, Transmission & Distribution 2020, 14, 2169 -2180.
AMA StyleCésar García Veloso, Kalle Rauma, Julián Fernández Orjuela, Christian Rehtanz. Real‐time agent‐based control of plug‐in electric vehicles for voltage and thermal management of LV networks: formulation and HIL validation. IET Generation, Transmission & Distribution. 2020; 14 (11):2169-2180.
Chicago/Turabian StyleCésar García Veloso; Kalle Rauma; Julián Fernández Orjuela; Christian Rehtanz. 2020. "Real‐time agent‐based control of plug‐in electric vehicles for voltage and thermal management of LV networks: formulation and HIL validation." IET Generation, Transmission & Distribution 14, no. 11: 2169-2180.
Kevin M. Banjar-Nahor; Florent Cadoux; Kalle Rauma; Nanang Hariyanto; Ngapuli Sinisuka. System Modeling and Its Effect on State Estimation in Unbalanced Low Voltage Networks in the Presence of Measurement Errors. 2019 2nd International Conference on High Voltage Engineering and Power Systems (ICHVEPS) 2019, 1 .
AMA StyleKevin M. Banjar-Nahor, Florent Cadoux, Kalle Rauma, Nanang Hariyanto, Ngapuli Sinisuka. System Modeling and Its Effect on State Estimation in Unbalanced Low Voltage Networks in the Presence of Measurement Errors. 2019 2nd International Conference on High Voltage Engineering and Power Systems (ICHVEPS). 2019; ():1.
Chicago/Turabian StyleKevin M. Banjar-Nahor; Florent Cadoux; Kalle Rauma; Nanang Hariyanto; Ngapuli Sinisuka. 2019. "System Modeling and Its Effect on State Estimation in Unbalanced Low Voltage Networks in the Presence of Measurement Errors." 2019 2nd International Conference on High Voltage Engineering and Power Systems (ICHVEPS) , no. : 1.
Alfio Spina; Kalle Rauma; Christoph Aldejohann; Mara Holt; Jonas Maasmann; Patrick Berg; Ulf Hager; Fritz Rettberg; Christian Rehtanz. Smart Grid Technology Lab – A Full-Scale Low Voltage Research Facility at TU Dortmund University. 2018 AEIT International Annual Conference 2018, 1 .
AMA StyleAlfio Spina, Kalle Rauma, Christoph Aldejohann, Mara Holt, Jonas Maasmann, Patrick Berg, Ulf Hager, Fritz Rettberg, Christian Rehtanz. Smart Grid Technology Lab – A Full-Scale Low Voltage Research Facility at TU Dortmund University. 2018 AEIT International Annual Conference. 2018; ():1.
Chicago/Turabian StyleAlfio Spina; Kalle Rauma; Christoph Aldejohann; Mara Holt; Jonas Maasmann; Patrick Berg; Ulf Hager; Fritz Rettberg; Christian Rehtanz. 2018. "Smart Grid Technology Lab – A Full-Scale Low Voltage Research Facility at TU Dortmund University." 2018 AEIT International Annual Conference , no. : 1.
This study contemplates the possibility of estimating in near real-time the extreme voltages (minimum and maximum phase-to-neutral voltages) in a low voltage (LV) network using some, but as little as possible, advanced metering infrastructure (AMI) data. The main target application is to control an on-load tap changer at a secondary substation (medium voltage/LV substations) so as to maintain adequate voltage in the entire downstream LV network. The authors focus on the practical problem that consists in choosing the customers whose (AMI-based) voltage measurements will be used as inputs to the voltage control. They propose a method for the selection of customers that is based solely on statistical load profiles (without the need to resort to past AMI data) and they assess it using real-world data from 38 different French urban and semi-urban LV networks. The authors’ results show that working with simple load profiles instead of large amounts of past AMI data is acceptable, and that in most cases, choosing only a set of about ten customers at most is sufficient to guarantee an almost negligible level of error in the estimation of the minimum and maximum voltages in the LV network.
Kalle Rauma; Florent Cadoux; Guillaume Roupioz; Adrien Dufournet; Nouredine Hadj‐Said. Optimal location of voltage sensors in low voltage networks for on‐load tap changer application. IET Generation, Transmission & Distribution 2017, 11, 3756 -3764.
AMA StyleKalle Rauma, Florent Cadoux, Guillaume Roupioz, Adrien Dufournet, Nouredine Hadj‐Said. Optimal location of voltage sensors in low voltage networks for on‐load tap changer application. IET Generation, Transmission & Distribution. 2017; 11 (15):3756-3764.
Chicago/Turabian StyleKalle Rauma; Florent Cadoux; Guillaume Roupioz; Adrien Dufournet; Nouredine Hadj‐Said. 2017. "Optimal location of voltage sensors in low voltage networks for on‐load tap changer application." IET Generation, Transmission & Distribution 11, no. 15: 3756-3764.
Inspec keywords: substations; power system measurement; photovoltaic power systems; voltage measurement; power meters; on load tap changers Subjects: Transformers and reactors; Voltage measurement; Solar power stations and photovoltaic power systems; Substations; Power system measurement and metering
Kalle Rauma; F. Cadoux; N. Hadj-Saïd; A. Dufournet; C. Baudot; G. Roupioz. Assessment of the MV/LV on-load tap changer technology as a way to increase LV hosting capacity for photovoltaic power generators. CIRED Workshop 2016 2016, 44 (4 .) -44 (4 .).
AMA StyleKalle Rauma, F. Cadoux, N. Hadj-Saïd, A. Dufournet, C. Baudot, G. Roupioz. Assessment of the MV/LV on-load tap changer technology as a way to increase LV hosting capacity for photovoltaic power generators. CIRED Workshop 2016. 2016; ():44 (4 .)-44 (4 .).
Chicago/Turabian StyleKalle Rauma; F. Cadoux; N. Hadj-Saïd; A. Dufournet; C. Baudot; G. Roupioz. 2016. "Assessment of the MV/LV on-load tap changer technology as a way to increase LV hosting capacity for photovoltaic power generators." CIRED Workshop 2016 , no. : 44 (4 .)-44 (4 .).
Harmonic is one of main concern in Wind Power Plant (WPP) as growing usage of power electronic converter is observed. Besides the injection of harmonic by individual wind turbine (WT) as source of harmonic, its propagation in network and problem of resonance is also an issue. By implementing passive filter for harmonic mitigation, additional resonance peak is observed due to its interaction with system side impedance. This paper explores the solution for harmonic mitigation with capability of damping resonance in WPP. An aggregated model of 400-MW WPP network is analyzed in correlating resonance and amplification. A passive filter and hybrid filter is designed to mitigate harmonic accordingly. It is shown that hybrid filter able to provide damping capability and improve the performance.
K.N Md Hasan; Kalle Rauma; Alvaro Luna; J. Ignacio Candela; Pedro Rodriguez. Harmonic resonance damping in Wind Power Plant. 2012 IEEE Energy Conversion Congress and Exposition (ECCE) 2012, 2067 -2074.
AMA StyleK.N Md Hasan, Kalle Rauma, Alvaro Luna, J. Ignacio Candela, Pedro Rodriguez. Harmonic resonance damping in Wind Power Plant. 2012 IEEE Energy Conversion Congress and Exposition (ECCE). 2012; ():2067-2074.
Chicago/Turabian StyleK.N Md Hasan; Kalle Rauma; Alvaro Luna; J. Ignacio Candela; Pedro Rodriguez. 2012. "Harmonic resonance damping in Wind Power Plant." 2012 IEEE Energy Conversion Congress and Exposition (ECCE) , no. : 2067-2074.
Harmonic resonance is among imperative aspect need to be analyzed in a wind power plant (WPP). It becomes complex since it involves a large network with high operating power. This paper presents a study on harmonic resonances in a WPP, particularly on parallel resonance. Important factors including length of cable, number of operating wind turbine and usage of output grid-side filter are analyzed. The damping of resonance by using common passive filter and an alternative hybrid filter is also explored. An aggregated WPP model of 400 MW with 40 wind turbines of 10 MW each are used as a study case.
K. N Md Hasan; Kalle Rauma; Alvaro Luna; J. Ignacio Candela; Pedro Rodriguez; José Ignacio Candela García. Study on harmonic resonances and damping in wind power plant. 2012 4th International Conference on Intelligent and Advanced Systems (ICIAS2012) 2012, 1, 418 -423.
AMA StyleK. N Md Hasan, Kalle Rauma, Alvaro Luna, J. Ignacio Candela, Pedro Rodriguez, José Ignacio Candela García. Study on harmonic resonances and damping in wind power plant. 2012 4th International Conference on Intelligent and Advanced Systems (ICIAS2012). 2012; 1 ():418-423.
Chicago/Turabian StyleK. N Md Hasan; Kalle Rauma; Alvaro Luna; J. Ignacio Candela; Pedro Rodriguez; José Ignacio Candela García. 2012. "Study on harmonic resonances and damping in wind power plant." 2012 4th International Conference on Intelligent and Advanced Systems (ICIAS2012) 1, no. : 418-423.
A detailed harmonic resonance analysis of power systems is more and more important due to the increasing number of power electronic devices. The topic is especially well-grounded in wind power plants that besides having several possible sources of harmonics have many inductive and capacitive elements. This combination forms a severe concern over harmonic resonance that composes a threat to the power quality and the function of wind power plants. This paper presents and applies the harmonic resonance mode analysis (HRMA) in a model of an off shore wind power plant with and without a passive filtering. The results of the harmonic resonance mode analysis are verified and compared with the results calculated with the frequency scan.
Kalle Rauma; K.N Md Hasan; Catalin Gavriluta; Constantino Citro. Resonance analysis of a wind power plant with modal approach. 2012 IEEE International Symposium on Industrial Electronics 2012, 2042 -2047.
AMA StyleKalle Rauma, K.N Md Hasan, Catalin Gavriluta, Constantino Citro. Resonance analysis of a wind power plant with modal approach. 2012 IEEE International Symposium on Industrial Electronics. 2012; ():2042-2047.
Chicago/Turabian StyleKalle Rauma; K.N Md Hasan; Catalin Gavriluta; Constantino Citro. 2012. "Resonance analysis of a wind power plant with modal approach." 2012 IEEE International Symposium on Industrial Electronics , no. : 2042-2047.
K.N. Md Hasan; Kalle Rauma; Alvaro Luna; J. Ignacio Candela; P. Rodriguez. Harmonic Resonance Study for Wind Power Plant. Renewable Energy and Power Quality Journal 2012, 1507 -1512.
AMA StyleK.N. Md Hasan, Kalle Rauma, Alvaro Luna, J. Ignacio Candela, P. Rodriguez. Harmonic Resonance Study for Wind Power Plant. Renewable Energy and Power Quality Journal. 2012; ():1507-1512.
Chicago/Turabian StyleK.N. Md Hasan; Kalle Rauma; Alvaro Luna; J. Ignacio Candela; P. Rodriguez. 2012. "Harmonic Resonance Study for Wind Power Plant." Renewable Energy and Power Quality Journal , no. : 1507-1512.