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

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

Frontiers in Energy Research ◽

10.3389/fenrg.2021.673165 ◽

2021 ◽

Vol 9 ◽

Author(s):

Surasit Sangob ◽

Somporn Sirisumrannukul

Keyword(s):

Energy Loss ◽

Electric Vehicles ◽

Distribution Systems ◽

Sequential Monte Carlo ◽

Low Voltage ◽

Cost Savings ◽

High Energy ◽

Voltage Regulation ◽

Sequential Optimization ◽

Smart Charging

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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On the Conflict between LVRT and Line Protection in LV Distribution Systems with PVs: A Current-Limitation-Based Solution

Energies ◽

10.3390/en12152909 ◽

2019 ◽

Vol 12 (15) ◽

pp. 2909 ◽

Cited By ~ 1

Author(s):

Aristotelis Tsimtsios ◽

Dionisis Voglitsis ◽

Ioannis Perpinias ◽

Christos Korkas ◽

Nick Papanikolaou

Keyword(s):

Distribution System ◽

Distribution Systems ◽

Low Voltage ◽

Energy Resource ◽

Distribution Networks ◽

Voltage Distribution ◽

Current Limitation ◽

Protection Scheme ◽

Low Voltage Ride Through ◽

Photovoltaic Generators

The upcoming adoption of low-voltage-ride-through requirements in low-voltage distribution systems is expected to raise significant challenges in the operation of grid-tied inverters. Typically, these inverters interconnect photovoltaic units, which are the predominant distributed energy resource in low-voltage distribution networks, under an umbrella of standards and protection schemes. As such, a challenging issue that should be considered in low-voltage distribution network applications, regards the coordination between the line protection scheme (typically consisting of a non-settable fuse) and the low-voltage-ride-through operation of photovoltaic generators. During a fault, the fuse protecting a low-voltage feeder may melt, letting the generator to continue its ride-through operation. Considering that the efficacy/speed of the anti-islanding detection is affected by ride-through requirements, this situation can lead to protracted energization of the isolated feeder after fuse melting (unintentional islanding). To address this issue, this paper proposes a fault-current-limitation based solution, which does not require any modification in the existing protection scheme. The operation principles, design, and implementation of this solution are presented, while, its effectiveness is supported by extensive simulations in a test-case low-voltage distribution system. A discussion on the presented results concludes the paper.

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A Voltage-Based Approach for Series High Impedance Fault Detection and Location in Distribution Systems Using Smart Meters

Energies ◽

10.3390/en12153022 ◽

2019 ◽

Vol 12 (15) ◽

pp. 3022 ◽

Cited By ~ 4

Author(s):

Francinei L. Vieira ◽

Pedro H. M. Santos ◽

José M. Carvalho Filho ◽

Roberto C. Leborgne ◽

Marino P. Leite

Keyword(s):

Distribution System ◽

Distribution Systems ◽

New Technologies ◽

Low Voltage ◽

Real Life ◽

Distribution Networks ◽

Smart Meters ◽

Voltage Unbalance ◽

High Impedance ◽

High Impedance Faults

High impedance faults (HIFs) have been a major concern for protecting distribution systems and public safety hazards when involving downed conductors. The deployment of smarter grids brings new technologies for smart monitoring, automation, and protection of distribution networks. This paper presents a new method for a series of HIF detection and location in primary distribution feeders, using voltage unbalance measurements collected from smart meters (SMs) installed at low-voltage end-users. The methodology was tested in MATLAB and Simulink through steady-state simulations of a typical 13.8 kV distribution system, under load unbalance and different fault scenarios. Results show that the proposed method is robust and accurate for the detection of blown fuses and broken conductors, with or without ground faults, located either at the source or the load-side. The ease of implementation in SM design, formulation of parameters, and reliable simulation results show potential real-life applications.

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Voltage Stability of Low-Voltage Distribution Grid with High Penetration of Photovoltaic Power Units

Energies ◽

10.3390/en11081960 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1960 ◽

Cited By ~ 9

Author(s):

Majid Ghaffarianfar ◽

Amin Hajizadeh

Keyword(s):

Power Distribution ◽

Distribution System ◽

Distribution Systems ◽

Voltage Stability ◽

Low Voltage ◽

Distribution Networks ◽

High Ratio ◽

Distribution Grid ◽

Negative Effects ◽

Loss Analysis

Voltage stability analysis of power distribution systems with high photovoltaic (PV) penetration is a challenging problem due to the stochastic generation of a solar power system. Voltage stability is an important benchmark for defining PV’s penetration level in active distribution networks considering loading capacity. The massive integration of PV power units, the effect of distribution system characteristics, like high ratio of R/X, and the reported collapses in power networks come up in serious studies that investigate their impact and upcoming problems on distribution networks. Therefore, this paper proposes analytical voltage stability and it is implemented on IEEE 34 nodes radial distribution systems with 24.9 kV and 4.16 kV voltage levels. In this regard, in addition to given properties in stability and power loss analysis, a penetration coefficient for PVs is considered. Simulation results prove that the applied method can illustrate the positive and negative effects of PV in distribution networks.

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Unit Template Based Control of PV-DSTATCOM

Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) ◽

10.2174/2352096511666181018112853 ◽

2020 ◽

Vol 13 (1) ◽

pp. 36-42

Author(s):

Gunjan Varshney ◽

Durg S. Chauhan ◽

Madhukar P. Dave ◽

Nitin

Keyword(s):

Power Quality ◽

Power Factor ◽

Power Distribution ◽

Distribution System ◽

Distribution Systems ◽

Phase Distribution ◽

Voltage Regulation ◽

Photovoltaic Array ◽

Quality Issues ◽

Static Compensator

Background: In modern electrical power distribution systems, Power Quality has become an important concern due to the escalating use of automatic, microprocessor and microcontroller based end user applications. Methods: In this paper, power quality improvement has done using Photovoltaic based Distribution Static Compensator (PV-DSTATCOM). Complete simulation modelling and control of Photovoltaic based Distribution Static Compensator have been provided in the presented paper. In this configuration, DSTATCOM is fed by solar photovoltaic array and PV module is also helpful to maintain the DC link voltage. The switching of PV-STATCOM is controlled by Unit template based control theory. Results: The performance of PV-DSTATCOM has been evaluated for Unity Power Factor (UPF) and AC Voltage Control (ACVC) modes. Here, for studying the power quality issues three-phase distribution system is considered and results have been verified through simulation based on MATLAB software. Conclusion: Different power quality issues and their improvement are studied and presented here for harmonic reduction, DC voltage regulation and power factor correction.

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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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Electric Vehicles in Jordan: Challenges and Limitations

Sustainability ◽

10.3390/su13063199 ◽

2021 ◽

Vol 13 (6) ◽

pp. 3199

Author(s):

Laith Shalalfeh ◽

Ashraf AlShalalfeh ◽

Khaled Alkaradsheh ◽

Mahmoud Alhamarneh ◽

Ahmad Bashaireh

Keyword(s):

Electric Vehicles ◽

Distribution System ◽

Distribution Systems ◽

Environmental Benefits ◽

System Stability ◽

Loading Conditions ◽

Stability Margins ◽

High Penetration ◽

Node Distribution ◽

The Impact

An increasing number of electric vehicles (EVs) are replacing gasoline vehicles in the automobile market due to the economic and environmental benefits. The high penetration of EVs is one of the main challenges in the future smart grid. As a result of EV charging, an excessive overloading is expected in different elements of the power system, especially at the distribution level. In this paper, we evaluate the impact of EVs on the distribution system under three loading conditions (light, intermediate, and full). For each case, we estimate the maximum number of EVs that can be charged simultaneously before reaching different system limitations, including the undervoltage, overcurrent, and transformer capacity limit. Finally, we use the 19-node distribution system to study these limitations under different loading conditions. The 19-node system is one of the typical distribution systems in Jordan. Our work estimates the upper limit of the possible EV penetration before reaching the system stability margins.

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A Head Formulation for the Steady-State Analysis of Water Distribution Systems Using an Explicit and Exact Expression of the Colebrook–White Equation

Water ◽

10.3390/w13091163 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1163

Author(s):

Mengning Qiu ◽

Avi Ostfeld

Keyword(s):

Steady State ◽

Distribution System ◽

Distribution Systems ◽

Water Distribution ◽

Solution Method ◽

Water Distribution System ◽

Academic Research ◽

Exact Expression ◽

Contamination Source

Steady-state demand-driven water distribution system (WDS) solution is the bedrock for much research conducted in the field related to WDSs. WDSs are modeled using the Darcy–Weisbach equation with the Swamee–Jain equation. However, the Swamee–Jain equation approximates the Colebrook–White equation, errors of which are within 1% for ϵ/D∈[10−6,10−2] and Re∈[5000,108]. A formulation is presented for the solution of WDSs using the Colebrook–White equation. The correctness and efficacy of the head formulation have been demonstrated by applying it to six WDSs with the number of pipes ranges from 454 to 157,044 and the number of nodes ranges from 443 to 150,630. The addition of a physically and fundamentally more accurate WDS solution method can improve the quality of the results achieved in both academic research and industrial application, such as contamination source identification, water hammer analysis, WDS network calibration, sensor placement, and least-cost design and operation of WDSs.

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Multi-objective optimization of optimal capacitor allocation in radial distribution systems

International Journal of Emerging Electric Power Systems ◽

10.1515/ijeeps-2019-0206 ◽

2020 ◽

Vol 21 (3) ◽

Author(s):

Sayed Mir Shah Danish ◽

Mikaeel Ahmadi ◽

Atsushi Yona ◽

Tomonobu Senjyu ◽

Narayanan Krishna ◽

...

Keyword(s):

Radial Distribution ◽

Distribution System ◽

Distribution Systems ◽

Reactive Power ◽

Stability Index ◽

Distribution Networks ◽

Optimization Method ◽

Optimal Size ◽

Multi Objective Optimization ◽

Multi Objective

AbstractThe optimal size and location of the compensator in the distribution system play a significant role in minimizing the energy loss and the cost of reactive power compensation. This article introduces an efficient heuristic-based approach to assign static shunt capacitors along radial distribution networks using multi-objective optimization method. A new objective function different from literature is adapted to enhance the overall system voltage stability index, minimize power loss, and to achieve maximum net yearly savings. However, the capacitor sizes are assumed as discrete known variables, which are to be placed on the buses such that it reduces the losses of the distribution system to a minimum. Load sensitive factor (LSF) has been used to predict the most effective buses as the best place for installing compensator devices. IEEE 34-bus and 118-bus test distribution systems are utilized to validate and demonstrate the applicability of the proposed method. The simulation results obtained are compared with previous methods reported in the literature and found to be encouraging.

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