Electricity

16 pages, 3927 KiB

Open AccessArticle

Adapted Stochastic PV Hosting Capacity Approach for Electric Vehicle Charging Considering Undervoltage

by Enock Mulenga, Math H. J. Bollen and Nicholas Etherden

Electricity 2021, 2(3), 387-402; https://doi.org/10.3390/electricity2030023 - 17 Sep 2021

Cited by 14 | Viewed by 2626

This paper presents a stochastic approach to single-phase and three-phase EV charge hosting capacity for distribution networks. The method includes the two types of uncertainties, aleatory and epistemic, and is developed from an equivalent method that was applied to solar PV hosting capacity [...] Read more.

This paper presents a stochastic approach to single-phase and three-phase EV charge hosting capacity for distribution networks. The method includes the two types of uncertainties, aleatory and epistemic, and is developed from an equivalent method that was applied to solar PV hosting capacity estimation. The method is applied to two existing low-voltage networks in Northern Sweden, with six and 83 customers. The lowest background voltage and highest consumption per customer are obtained from measurements. It is shown that both have a big impact on the hosting capacity. The hosting capacity also depends strongly on the charging size, within the range of charging size expected in the near future. The large range in hosting capacity found from this study—between 0% and 100% of customers can simultaneously charge their EV car—means that such hosting capacity studies are needed for each individual distribution network. The highest hosting capacity for the illustrative distribution networks was obtained for the 3.7 kW single-phase and 11 kW three-phase EV charging power. Full article

(This article belongs to the Collection Optimal Operation and Planning of Smart Power Distribution Networks)

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29 pages, 5002 KiB

Open AccessReview

Thermoelectric Power Generators: State-of-the-Art, Heat Recovery Method, and Challenges

by Rima Aridi, Jalal Faraj, Samer Ali, Thierry Lemenand and Mahmoud Khaled

Electricity 2021, 2(3), 359-386; https://doi.org/10.3390/electricity2030022 - 16 Sep 2021

Cited by 27 | Viewed by 11281

Abstract

Electricity plays a significant role in daily life and is the main component of countless applications. Thus, ongoing research is necessary to improve the existing approaches, or find new approaches, to enhancing power generation. The thermoelectric generator (TEG) is among the notable and [...] Read more.

Electricity plays a significant role in daily life and is the main component of countless applications. Thus, ongoing research is necessary to improve the existing approaches, or find new approaches, to enhancing power generation. The thermoelectric generator (TEG) is among the notable and widespread technologies used to produce electricity, and converts waste energy into electrical energy using the Seebeck effect. Due to the Seebeck effect, temperature change can be turned into electrical energy; hence, a TEG can be applied whenever there is a temperature difference. The present paper presents the theoretical background of the TEG, in addition to a comprehensive review of the TEG and its implementation in various fields. This paper also sheds light on the new technologies of the TEG and their related challenges. Notably, it was found that the TEG is efficient in hybrid heat recovery systems, such as the phase change material (PCM), heat pipe (HP), and proton exchange membrane (PEM), and the efficiency of the TEG has increased due to a set of improvements in the TEG’s materials. Moreover, results show that the TEG technology has been frequently applied in recent years, and all of the investigated papers agree that the TEG is a promising technology in power generation and heat recovery systems. Full article

(This article belongs to the Special Issue Electromagnetic Compatibility in Power Systems and Smart Cities)

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17 pages, 6851 KiB

Open AccessArticle

Procedure for Verifying Population Exposure Limits to the Magnetic Field from Double-Circuit Overhead Power Lines

by Marco Landini, Giovanni Mazzanti and Riccardo Mandrioli

Electricity 2021, 2(3), 342-358; https://doi.org/10.3390/electricity2030021 - 12 Sep 2021

Cited by 2 | Viewed by 2831

Abstract

The verification of the limits of the population’s exposure to the magnetic field generated by double-circuit power lines from field measurements carried out on site is not trivial. It requires knowledge of the power line current instant values during the measurement period, the [...] Read more.

The verification of the limits of the population’s exposure to the magnetic field generated by double-circuit power lines from field measurements carried out on site is not trivial. It requires knowledge of the power line current instant values during the measurement period, the determination of the relationship between current and field at the measurement points (made more complex by the double-circuit overhead line configuration) and the use of that relationship to extrapolate the field values. Nevertheless, the verification of exposure limits for double-circuit power lines from on-site measurements is often conducted with rough, or not particularly stringent, procedures. A practical and straightforward procedure of general validity for non-optimized double-circuit lines is proposed here. No specific measurement position or conductors disposition knowledge is required as well as no complex three-dimensional finite element method code is necessary. The procedure, potentially also applicable to high- and extra-high-voltage lines, is validated on a medium-voltage (15 kV) double-circuit overhead power line study case. Exposure limits assessment suggests that if the line is operated at its rated capacity (230/285 A), the 3 μT quality target is missed. Results are provided with a 95% confidence interval ranging from ±100 nT to ±140 nT in all the cases. Full article

(This article belongs to the Special Issue Electromagnetic Compatibility in Power Systems and Smart Cities)

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12 pages, 6043 KiB

Open AccessConcept Paper

Phasor Measurement Unit Assisted Inverter—A Novel Approach for DC Microgrids Performance Enhancement

by Raziq Yaqub

Electricity 2021, 2(3), 330-341; https://doi.org/10.3390/electricity2030020 - 24 Aug 2021

Cited by 6 | Viewed by 3303

Abstract

DC microgrids are set to change the landscape of future energy markets. However, a wide-scale deployment faces three major issues: initial synchronization of microgrid with the utility grid, slip management during its operation, and mitigation of distortions produced by the inverter. This paper [...] Read more.

DC microgrids are set to change the landscape of future energy markets. However, a wide-scale deployment faces three major issues: initial synchronization of microgrid with the utility grid, slip management during its operation, and mitigation of distortions produced by the inverter. This paper proposes a Phasor Measurement Unit (PMU) Assisted Inverter (PAI) that addresses these three issues in a single solution. The proposed PAI continually receives real-time data from a Phasor Measurement Unit installed in the distribution system of a utility company and keeps constructing a real-time reference signal for the inverter. A well-constructed, real-time reference signal plays a vital role in addressing the above issues. The results show that the proposed PAI is 97.95% efficient. Full article

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14 pages, 821 KiB

Open AccessArticle

Reduction in the Electromagnetic Interference Generated by AC Overhead Power Lines on Buried Metallic Pipelines with Screening Conductors

by Arturo Popoli, Leonardo Sandrolini and Andrea Cristofolini

Electricity 2021, 2(3), 316-329; https://doi.org/10.3390/electricity2030019 - 19 Aug 2021

Cited by 5 | Viewed by 2892

Abstract

This paper presents a numerical study on the reduction in the voltage and current induced on a

13.5

km buried metallic pipeline by an overhead power line. The mitigation effectiveness of different configurations and cross-section shapes of screening conductors is computed by means [...] Read more.

This paper presents a numerical study on the reduction in the voltage and current induced on a

13.5

km buried metallic pipeline by an overhead power line. The mitigation effectiveness of different configurations and cross-section shapes of screening conductors is computed by means of a methodology that combines a 2D Finite Element Analysis with circuital analysis. A

35.72

% reduction of the maximum induced voltage is obtained when 4 cylindrical steel screening conductors with 8

mm

radius are buried

0.25

m

below the soil surface, along the pipeline path. The maximum induced pipeline current is reduced by

26.98

%. A parametric study is also performed, to assess the influence of the per-unit-length admittance to earth of the screening conductors on the mitigation efficacy. The results show that screening conductors may help in reducing the inductive coupling between overhead power lines and buried metallic pipelines, and that the assumption of perfectly insulated screening conductors leads to an underestimation of the produced mitigation effect. Full article

(This article belongs to the Special Issue Electromagnetic Compatibility in Power Systems and Smart Cities)

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16 pages, 3531 KiB

Open AccessArticle

A Methodology to Analyze and Evaluate the Uncertainty Propagation due to Temperature and Frequency and Design Optimization for EMC Testing Instrumentation

by Marco Bosi, Albert-Miquel Sánchez, Francisco Javier Pajares and Lorenzo Peretto

Electricity 2021, 2(3), 300-315; https://doi.org/10.3390/electricity2030018 - 12 Aug 2021

Cited by 4 | Viewed by 2833

Abstract

This paper presents a study and proposes a new methodology to analyze, evaluate and reduce the overall uncertainty of instrumentations for EMC measurements. For the scope of this work, the front end of a commercial EMI receiver is chosen and variations due to [...] Read more.

This paper presents a study and proposes a new methodology to analyze, evaluate and reduce the overall uncertainty of instrumentations for EMC measurements. For the scope of this work, the front end of a commercial EMI receiver is chosen and variations due to tolerances, temperature and frequency response of the system are evaluated. This paper illustrates in detail how to treat each block composing the model by analyzing each discrete component, and how to evaluate their influence on the measurand. Since a model can have hundreds or even thousands of parameters, the probability distribution functions (PDFs) of some variable might be unknown. So, a method that allows to obtain in a fast and easy way the uncertainty of the measurement despite having so many variables, to then being able to evaluate the influence of each component on the measurand, is necessary for a correct design. In this way, it will be possible to indicate which discrete components have the most influence on the measurand and thus set the maximum tolerances allowed and being able to design a cost-effective solution. Furthermore, this works presents a methodology which can easily be extended and applied to estimate and compute the uncertainty for electromagnetic interferences, energy storage systems (ESS), energy production, electric machines, electric transports and power plants in general. Full article

(This article belongs to the Special Issue Electromagnetic Compatibility in Power Systems and Smart Cities)

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15 pages, 20223 KiB

Open AccessArticle

Assessment of the Visual Impact of Existing High-Voltage Lines in Urban Areas

by Andreas Sumper, Oriol Boix-Aragones, Joan Rull-Duran, Joan Amat-Algaba and Joachim Wagner

Electricity 2021, 2(3), 285-299; https://doi.org/10.3390/electricity2030017 - 29 Jul 2021

Cited by 4 | Viewed by 3567

Abstract

This article proposes a novel methodology to evaluate the visual impact of high-voltage lines in urban areas based on photographic images. The use of photographs allows for calculating the overall aesthetic impact while eliminating the subjective factors of the observer. To apply the [...] Read more.

This article proposes a novel methodology to evaluate the visual impact of high-voltage lines in urban areas based on photographic images. The use of photographs allows for calculating the overall aesthetic impact while eliminating the subjective factors of the observer. To apply the proposed methodology based on photographs, the impact of the position and angle where the photograph was taken was analyzed, and a sensibility analysis was carried out. Moreover, it was applied to an application case, and a comparison with results from a previous study of a visual impact was performed. The methodology shows good performance and a better resolution of the indicator. Full article

(This article belongs to the Collection Optimal Operation and Planning of Smart Power Distribution Networks)

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14 pages, 1085 KiB

Open AccessArticle

Design Techniques for Low-Power and Low-Voltage Bandgaps

by Edoardo Barteselli, Luca Sant, Richard Gaggl and Andrea Baschirotto

Electricity 2021, 2(3), 271-284; https://doi.org/10.3390/electricity2030016 - 26 Jul 2021

Cited by 9 | Viewed by 4994

Abstract

Reverse bandgaps generate PVT-independent reference voltages by means of the sums of pairs of currents over individual matched resistors: one (CTAT) current is proportional to V_EB; the other one (PTAT) is proportional to V_T (Thermal voltage). Design guidelines and techniques [...] Read more.

Reverse bandgaps generate PVT-independent reference voltages by means of the sums of pairs of currents over individual matched resistors: one (CTAT) current is proportional to V_EB; the other one (PTAT) is proportional to V_T (Thermal voltage). Design guidelines and techniques for a CMOS low-power reverse bandgap reference are presented and discussed in this paper. The paper explains firstly how to design the components of the bandgap branches to minimize circuit current. Secondly, error amplifier topologies are studied in order to reveal the best one, depending on the operation conditions. Finally, a low-voltage bandgap in 65 nm CMOS with 5 ppm/°C, with a DC PSR of −91 dB, with power consumption of 5.2 μW and with an area of 0.0352 mm² developed with these techniques is presented. Full article

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27 pages, 9242 KiB

Open AccessReview

Comparison of DSOGI-Based PLL for Phase Estimation in Three-Phase Weak Grids

by Jorge Pinto, Adriano Carvalho, Agostinho Rocha and Armando Araújo

Electricity 2021, 2(3), 244-270; https://doi.org/10.3390/electricity2030015 - 08 Jul 2021

Cited by 9 | Viewed by 4642

Abstract

The paper presents a summary of different double second-order generalized integrator (DSOGI)-based phase-locked loop (PLL) algorithms for synchronization with three-phase weak grids. The different methods are compared through simulation under a variety of grid conditions, such as unbalanced phase voltages, high low-order harmonics [...] Read more.

The paper presents a summary of different double second-order generalized integrator (DSOGI)-based phase-locked loop (PLL) algorithms for synchronization with three-phase weak grids. The different methods are compared through simulation under a variety of grid conditions, such as unbalanced phase voltages, high low-order harmonics distortion, frequency steps, phase jumps, and voltage sags. Following the simulation results, the three methods that have shown the overall best results are compared through an experimental setup for further results validation under operation with a voltage-source converter. Based on the obtained results, a benchmark table is presented that allows ranking the performance of the tested methods for different expected grid conditions. Full article

(This article belongs to the Collection Optimal Operation and Planning of Smart Power Distribution Networks)

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19 pages, 4649 KiB

Open AccessArticle

Electric Vehicles as a Flexibility Provider: Optimal Charging Schedules to Improve the Quality of Charging Service

by Kalle Rauma, Alexander Funke, Toni Simolin, Pertti Järventausta and Christian Rehtanz

Electricity 2021, 2(3), 225-243; https://doi.org/10.3390/electricity2030014 - 24 Jun 2021

Cited by 8 | Viewed by 2807

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Recent Advances in Energy Storage Systems)

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Electricity, Volume 2, Issue 3 (September 2021) – 10 articles

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