Optimal Sequential Distribution Planning for Low-Voltage Network With Electric Vehicle Loads

There has been a growing presence of electric vehicles in many countries including Thailand, where many forms of incentives have been provided to build integrated infrastructure, and to encourage drivers to switch to electric vehicles (EVs). Because the immediate entry of EVs unavoidably can alter household load profiles, reinforcement on the existing system based on traditional planning may not be sufficient and can introduce over or under capital and operating expenditure over the time horizon. Therefore, if distribution systems are unreadily prepared for such an uptake, three obvious problems can be expected: 1) voltage regulation, 2) overloads of the distribution feeders and the distribution transformers, and 3) high energy loss. In this paper, an activity-based, time-sequential Monte Carlo Simulation algorithm was comprehensively developed for uncontrollable and smart charging, given annually updated information of EV locations and number of EVs, their energy consumption, hourly average vehicle speed, number of daily trips, travel distance per trip, size of EV batteries, time to arrive home and time to leave home. Minimizing the annual sum of investment and operating costs over a planning period could then be sequentially solved by a Particle Swarm Optimization (PSO) algorithm. The results from a practical 122-bus, 24 kV/400 V distribution system with different scenarios of uncontrollable and smart charging show that the sequential optimization embedded with deterministic decision can help improve customer voltage profile, keep feeder and transformer loading within acceptable operating limits and offer significant cost savings from energy loss. As far as a large number of low-voltage networks, and the associated large sum of cost savings are concerned, the proposed planning framework is practical to be applied and expected to be served as a new guideline for future implementation in Thailand.

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Investigation on Using Low Voltage Automatic Regulation to Minimize the Impacts of Charging Plug-in Electric Vehicles in Distribution Systems

Renewable Energy and Power Quality Journal ◽

10.24084/repqj19.222 ◽

2021 ◽

Vol 19 ◽

pp. 85-90

Author(s):

Priscila Costa Nascimento ◽

◽

Michel Girotto de Oliveira ◽

José Carlos M. Vieira

Keyword(s):

Steady State ◽

Electric Vehicles ◽

Distribution System ◽

Distribution Systems ◽

Low Voltage ◽

Electric Energy ◽

Distribution Networks ◽

Voltage Regulation ◽

Automatic Regulation ◽

Electric Energy Storage

The growth of micro and mini distributed generation and, more recently, the use of electric energy storage systems and the incentives for electric mobility are important examples of the transformations that distribution networks have been going through. In this context, this paper firstly presents the impacts of uncoordinated plug-in electric vehicles (PEVs) charging in a real Brazilian distribution system. Four scenarios were elaborated with different PEVs penetration levels and the results show increased voltage unbalance, system losses, and violations of the steady-state voltage limits, even in the presence of an automatic voltage regulator installed in the medium voltage network. Then, as the main contribution, the potential usage of automatic voltage regulation at the low voltage network was investigated to minimize the negative impacts of uncontrolled PEV charging on distribution system steady-state operation. It is important to highlight that this is not a common practice of utilities in Brazil. The obtained results showed that regulating the voltage at the low voltage side could be an effective solution to keep the voltages within statutory limits.

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Optimized Strategic Planning of Future Norwegian Low-Voltage Networks with a Genetic Algorithm Applying Empirical Electric Vehicle Charging Data

Electricity ◽

10.3390/electricity2010006 ◽

2021 ◽

Vol 2 (1) ◽

pp. 91-109

Author(s):

Julian Wruk ◽

Kevin Cibis ◽

Matthias Resch ◽

Hanne Sæle ◽

Markus Zdrallek

Keyword(s):

Genetic Algorithm ◽

Electric Vehicle ◽

Electric Vehicles ◽

Low Voltage ◽

Network Planning ◽

Voltage Regulation ◽

Electric Vehicle Charging ◽

Vehicle Charging ◽

The Impact

This article outlines methods to facilitate the assessment of the impact of electric vehicle charging on distribution networks at planning stage and applies them to a case study. As network planning is becoming a more complex task, an approach to automated network planning that yields the optimal reinforcement strategy is outlined. Different reinforcement measures are weighted against each other in terms of technical feasibility and costs by applying a genetic algorithm. Traditional reinforcements as well as novel solutions including voltage regulation are considered. To account for electric vehicle charging, a method to determine the uptake in equivalent load is presented. For this, measured data of households and statistical data of electric vehicles are combined in a stochastic analysis to determine the simultaneity factors of household load including electric vehicle charging. The developed methods are applied to an exemplary case study with Norwegian low-voltage networks. Different penetration rates of electric vehicles on a development path until 2040 are considered.

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Smart charging for electric vehicles to minimise charging cost

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650916688409 ◽

2017 ◽

Vol 231 (6) ◽

pp. 526-534 ◽

Cited By ~ 5

Author(s):

Yue Wang ◽

David Infield ◽

Simon Gill

Keyword(s):

Electric Vehicle ◽

Electric Vehicles ◽

Distribution System ◽

Power Flow ◽

Optimal Power Flow ◽

Low Voltage ◽

Wholesale Price ◽

Heuristic Method ◽

Domain Model ◽

Smart Charging

This paper assumes a smart grid framework where the driving patterns for electric vehicles are known, time variations in electricity prices are communicated to householders, and data on voltage variation throughout the distribution system are available. Based on this information, an aggregator with access to this data can be employed to minimise electric vehicles charging costs to the owner whilst maintaining acceptable distribution system voltages. In this study, electric vehicle charging is assumed to take place only in the home. A single-phase Low Voltage (LV) distribution network is investigated where the local electric vehicles penetration level is assumed to be 100%. Electric vehicle use patterns have been extracted from the UK Time of Use Survey data with a 10-min resolution and the domestic base load is generated from an existing public domain model. Apart from the so-called real time price signal, which is derived from the electricity system wholesale price, the cost of battery degradation is also considered in the optimal scheduling of electric vehicles charging. A simple and effective heuristic method is proposed to minimise the electric vehicles’ charging cost whilst satisfying the requirement of state of charge for the electric vehicles’ battery. A simulation in OpenDSS over a period of 24 h has been implemented, taking care of the network constraints for voltage level at the customer connection points. The optimisation results are compared with those obtained using dynamic optimal power flow.

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Probabilistic Harmonic Analysis for Waveform Distortion Assessment of Low Voltage Distribution Systems with Plug-in Hybrid Electric Vehicles

2019 1st International Conference on Energy Transition in the Mediterranean Area (SyNERGY MED) ◽

10.1109/synergy-med.2019.8764126 ◽

2019 ◽

Author(s):

Pierluigi Caramia ◽

Daniela Proto ◽

Angela Russo ◽

Pietro Varilone

Keyword(s):

Harmonic Analysis ◽

Electric Vehicles ◽

Distribution Systems ◽

Hybrid Electric Vehicles ◽

Low Voltage ◽

Voltage Distribution ◽

Waveform Distortion ◽

Hybrid Electric

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Investigation of Var Compensation Schemes in Unbalanced Distribution Systems

Complexity ◽

10.1155/2019/7824743 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Yinuo Huang ◽

Licheng Wang ◽

Kai Wang

Keyword(s):

Distribution System ◽

Distribution Systems ◽

Low Voltage ◽

Current System ◽

Voltage Regulation ◽

Voltage Sensitivity ◽

Compensation Methods ◽

Distribution System Planning ◽

Var Compensation ◽

Phase Conductors

Distributed rooftop photovoltaic (PV) generators prospered distributed generation (DG) in recent years. Certain randomness of rooftop PV connection may lead to significant PV power imbalance across three phases, especially in low-voltage distribution systems. Due to interphase line coupling, traditional Var compensation methods which typically have competent voltage regulation performance may become less effective in such PV imbalance scenarios. In this paper, the limitation of traditional Var compensation methods in voltage regulation with unbalanced PV power integration is demonstrated and comprehensively analyzed. After describing the voltage regulation challenge, based on the voltage sensitivity analysis, it is revealed that PV power unbalanced level together with equivalent mutual impedance among phase conductors has a significant impact on the effectiveness of traditional Var compensation methods on voltage regulation. On this basis, to improve the performance of voltage regulation methods, some suggestions are proposed for both current system operation and future distribution system planning. Numerical studies demonstrate the effectiveness of the proposed suggestions. Future rooftop PV integration in LV systems can benefit from this research.

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Local versus centralized charging strategies for electric vehicles in low voltage distribution systems

2013 IEEE Power & Energy Society General Meeting ◽

10.1109/pesmg.2013.6672380 ◽

2013 ◽

Cited By ~ 1

Author(s):

Peter Richardson ◽

Damian Flynn ◽

Andrew Keane

Keyword(s):

Electric Vehicles ◽

Distribution Systems ◽

Low Voltage ◽

Voltage Distribution

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Analysis of Voltage Unbalance and Energy Loss in Residential Low Voltage Distribution Systems with Rooftop Photovoltaic Systems

E3S Web of Conferences ◽

10.1051/e3sconf/202019000033 ◽

2020 ◽

Vol 190 ◽

pp. 00033

Author(s):

Rattanaprapa Charoenwattana ◽

Umarin Sangpanich

Keyword(s):

Energy Loss ◽

Distribution Systems ◽

Low Voltage ◽

Energy Losses ◽

Photovoltaic Systems ◽

Housing Estate ◽

Voltage Distribution ◽

Pv System ◽

Voltage Unbalance ◽

Pv Systems

This paper investigates effects of voltage unbalance and energy losses due to the connection of rooftop photovoltaic systems in a low voltage distribution system of a housing estate, which has light loads during daytime. The paper presents a case study of a real distribution power system of housing estate in Thailand. Voltage unbalance and energy losses were simulated by using system characteristic and load data from GIS database of PEA with the DIgSILENT Power Factory program. The key findings of our analysis are as follows. Firstly, the number of installable 1-phase rooftop PV systems varies directly with load density. Secondly, the number of installed 1-phase rooftop PV systems can be increased if the installation locations are closer to the transformer. For 3-phase rooftop PV systems, their installations do not have any effects on the voltage unbalance. Furthermore, system energy loss relates to the load density and PV system installation locations in the same way as the voltage unbalance. The key implication of our study is that the installation of 1-phase rooftop PV system should be granted based on a careful consideration of the installation location and the load density.

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Battery Discharging Power Control in a Double-Wound Flywheel System Applied to Electric Vehicles

International Journal of Emerging Electric Power Systems ◽

10.2202/1553-779x.2674 ◽

2011 ◽

Vol 12 (1) ◽

Author(s):

Janaína Goncalves de Oliveira ◽

Johan Abrahamsson ◽

Hans Bernhoff

Keyword(s):

Energy Storage ◽

Electric Vehicles ◽

Peak Power ◽

Low Voltage ◽

Good Alternative ◽

High Energy ◽

High Energy Density ◽

Power Capacity ◽

Control Logic ◽

Efficient System

Flywheel Energy Storage Systems (FESS) are a good alternative for power handling and energy storage in hybrid and electric vehicles. The combination of a FESS and a battery has several advantages, such as higher peak power capacity and reduced number of charging/discharging cycles in the battery. Nevertheless, batteries have a significant effect on the performance of the system and the control of the flywheel-battery link should be optimized in order to increase the system efficiency.The FESS investigated in this paper has its novelty in the use of a double wound flywheel machine which divides the system in two different voltage/power levels. High-Voltage/Power (HV) side connects the flywheel machine to the wheel motor and Low-Voltage/Power (LV) side connects the flywheel machine to the battery.The present paper focuses on the converter system and the control logic which regulates battery discharging process and the flywheel rotational speed. Emphasis has been given to the overall power/energy management of the system. Simulations and experimental results show that an ON/OFF battery control allows a highly efficient system, requiring a robust speed control and high energy density for the flywheel machine.

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Design and Implementation of Novel Multi-Converter-Based Unified Power Quality Conditioner for Low-Voltage High-Current Distribution System

Energies ◽

10.3390/en11113150 ◽

2018 ◽

Vol 11 (11) ◽

pp. 3150 ◽

Cited By ~ 3

Author(s):

Bin Yang ◽

Kangli Liu ◽

Sen Zhang ◽

Jianfeng Zhao

Keyword(s):

Power Quality ◽

Current Distribution ◽

Distribution Systems ◽

Reactive Power ◽

Low Voltage ◽

Voltage Regulation ◽

Control Algorithms ◽

High Current ◽

Unified Power Quality Conditioner ◽

Power Quality Conditioner

This paper introduces a novel multi-converter-based unified power quality conditioner (MCB-UPQC). Three optimization methods are proposed based on the traditional UPQC: (1) The shunt converter is substituted with multi-modular parallel converters. Hence, the reactive power and harmonic currents can be increased greatly, which are suitable for low-voltage high-current distribution systems. (2) The series converters consist of three H-bridge inverters, and each of the H-bridge inverters is controlled separately. The control strategy is easier to achieve and can improve the control performance of voltage regulation under unbalanced voltage sag or swell. (3) A three-phase four-leg (3P4L) converter is connected to the common DC bus of the proposed UPQC to connect the renewable energy and energy storage system. The detailed mathematical models of shunt and series converters are analyzed, respectively. A multi-proportional resonant (PR) controller is presented in the voltage regulation and reactive power compensation control algorithms. The simulation results verify the feasibility of the control algorithms. Finally, the experimental platform is established, and the experimental results are presented to verify the validity and superiority of the proposed topology and algorithms.

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