Cited by 12Electric Vehicles and InfrastructureOptimal Power Flow DistributionSmart Grid Energy Management

Hosting Capacity Assessment of South African Residential Low-Voltage Networks for Electric Vehicle Charging

Open access
Umoh, Vincent, Adebiyi, Abayomi, Moloi, Katleho·2023·Eng

Abstract

The necessity for environmentally friendly transportation systems has prompted the proliferation of electric vehicles (EVs) in low-voltage (LV) distribution networks. However, large-scale integration and simultaneous charging of EVs can create power quality challenges for the distribution grid. It is therefore important to assess the impact of connecting EVs for charging in existing distribution networks and determine the hosting capacity (HC) of such a network. This paper uses a deterministic time-series method and stochastic method based on a simplified Monte Carlo simulation to estimate the HC of single-phase and three-phase EV charging, respectively, for a South African low-voltage distribution network containing 21 households. Voltage drop and equipment loading are the performance indices (PI) considered for the impact assessment and HC estimation in this study. The impact assessment result confirms that increasing EV charging penetration will result in a corresponding movement of the PIs toward the allowable limits. The results show that the HC is 5–8 three-phase EVs charging simultaneously for the worst-case scenario and 9–13 EVs for the best-case scenario. Furthermore, the single-phase HC for the popular 3.7 kW EV charger is 15 and 8 EVs for the best-case and worst-case scenarios, respectively. The result showing the seasonal variation in HC and for other EV charging power is also presented. The difference in HC for the worst-case and best-case scenarios portrays the effect that the location of charging has on the HC.

AI snapshot

Written from the paper’s full text.

TL;DR

This paper assesses EV charging hosting capacity on a 21-household South African low-voltage network using deterministic time-series and simplified Monte Carlo methods. It finds equipment loading is the main limiting factor, with three-phase HC of 5–8 EVs worst-case and 9–13 best-case, and single-phase 3.7 kW HC of 8 worst-case and 15 best-case.

Key findings

  • Three-phase EV charging HC is 5–8 EVs charging simultaneously for the worst-case scenario and 9–13 EVs for the best-case scenario; seasonal analysis shows the network can host more EVs in summer (13 best-case, 8 worst-case) and fewest in winter.
  • Equipment loading is the major limiting factor. In the three-phase worst-case, the first loading violation is at 108% at 29% penetration (6 customers); in the best-case, the first loading violation is at 107% when 10 customers (48% penetration) charge.
  • For single-phase charging, the popular 3.7 kW charger has HC of 8 EVs worst-case and 15 EVs best-case; Table 2 reports voltage-drop HC of 10 worst-case and 15 best-case, and equipment-loading HC of 8 worst-case and 10 best-case. For an 11.5 kW charger, equipment-loading HC is 0 worst-case and 5 best-case.
  • During the best-case scenario, 9 and 10 customers can be hosted simultaneously for 85% and 70% of hours, respectively; during the worst-case, 5 and 6 customers can charge simultaneously for 85% and 60% of the year without violating any performance index.

Methods

  • Test network: part of an eThekwini power grid in Durban, South Africa, consisting of 21 high-income homes, supplied by a 350 kVA 11/0.41 kV Dyn11 transformer, with three customers per distribution unit and one EV assumed per customer.
  • Data and modelling: one calendar year (2021) of measured hourly average active energy for all 21 customers from eThekwini Municipality; load scaling in DIgSILENT PowerFactory 2022; 15 July 2021 used as the critical day for single-phase assessment.
  • Analysis: deterministic/time-series method for three-phase HC; stochastic simplified Monte Carlo simulation for single-phase HC with phase selection as the only uncertainty, 500 scenarios, and 16:00–18:00 on the critical day; performance indices are voltage drop and equipment loading, with limits from NRS097 (loading 100%, voltage not below 0.90 p.u.), assuming uncontrolled charging without state of charge.

Limitations

  • Stated: results are specific to one grid, performance index, and PI limits, and cannot be immediately transferred to other non-homogenous distribution grids.
  • Stated: the study uses uncontrolled EV charging without considering charging behaviour or battery state of charge, which may underestimate HC; future work should consider controlled charging, state of charge, and different customer charging behaviours.
  • Evident from the text: single-phase Monte Carlo considers only phase selection as uncertainty; individual household load data were unavailable, so all customers were assumed to have the same consumption pattern via load scaling; the single-phase assessment relies on one critical day and assumes no violation then implies likely no violation in other periods.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3390/eng4030111

Cites

21 of 21 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

1 of 7 cited sources checked · 0 supported · 0 flagged · accuracy not yet measured

  • Findingown data

    Increasing EV penetration level results in a corresponding increase in equipment loading towards the allowable limit in the single-phase network.

    “It is observed that increasing the penetration level results in a corresponding increase in the equipment loading towards the allowable limit.”
    Quote in the paperSubstantial claim
  • Findingown data

    The single-phase hosting capacity result shows that 48% to 76% of the customers can charge simultaneously when voltage drop is the PI considered.

    “Also, the single-phase HC result presented shows that 48% to 76% of the customers can charge simultaneously when the voltage drop is the PI considered.”
    Quote in the paperSubstantial claim
  • Findingown data

    For single-phase voltage drop as PI, the hosting capacity reduces to 9.5% and 57% at 6.9 kW charging power.

    “The HC reduces to 9.5% and 57% at 6.9 kW charging power.”
    Quote in the paperSubstantial claim
  • Findingown data

    In the three-phase best-case scenario, the first voltage violation is observed at 57% PL EV when 12 EVs are simultaneously charging.

    “Figure 8b shows the best-case scenario where the first violation is observed at 57% PL EV , when 12 EVs are simultaneously charging.”
    Quote in the paperSubstantial claim
  • Findingown data

    In the three-phase worst-case scenario, more customers can charge at hours of lower household load demand until both minimum and maximum equipment loading exceed the limits when nine EVs (43% PL EV) are simultaneously charging.

    “More customers can charge at hours of lower household load demand until both minimum and maximum equipment loading exceed the limits when nine EVs (43% PL EV ) are simultaneously charging.”
    Quote in the paperSubstantial claim
  • May combine two claims. 15
  • Classified as probably not a substantial claim. 2
  • May combine two claims.

    Premisecitation

    The growing sales of plug-in electric vehicles imply that EV charging in the distribution network is increasing, translating into increased peak power consumption and changes in consumption patterns.

    “The growing sales of plug-in electric vehicles [3] imply that EV charging in the distribution network is increasing, and this translates into a corresponding increase in peak power consumption and changes in consumption patterns [4,5].”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [3] (2022, November 11). EV Sales. Available online: https://cleantechnica.com/tag/ev-sales/.

      Not checked in the free run.

    • cites [4] Ping, 2020, A two-stage autonomous EV charging coordination method enabled by blockchain, J. Mod. Power Syst. Clean Energy source

      The Introduction says increasing EV penetration in distribution networks creates overload risks. Coordination Results reports that uncoordinated charging exceeds the network’s load limit during peak hours, while coordination shifts charging to neighboring hours. This supports the peak-load concern, but the paper attributes the change in the load pattern to coordination, not directly to growing EV sales or charging demand. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [5] Shepero, 2018, Modeling of photovoltaic power generation and electric vehicles charging on city-scale: A review, Renew. Sustain. Energy Rev. source
  • May combine two claims.

    Findingown data

    The test network can host more customers with EVs during summer (13 for best-case and eight for worst-case) and the fewest during winter.

    “The test network can host more customers (13 and eight for best-case and worst-case scenario, respectively) with EVs during the summer while the fewest number of EVs can be connected during the winter.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    For single-phase equipment loading as PI, the hosting capacity with a 3.7 kW charger is eight customers for the worst-case and 10 customers for the best-case scenario.

    “Moreover, for the popular 3.7 kW charger, the HC is eight customers for the worst-case and 10 customers for the best-case scenario.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    The single-phase hosting capacity for the 3.7 kW EV charger is 15 EVs for the best-case scenario and 8 EVs for the worst-case scenario.

    “Furthermore, the single-phase HC for the popular 3.7 kW EV charger is 15 and 8 EVs for the best-case and worst-case scenarios, respectively.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Each customer is capable of connecting only one EV to the grid.
    • The authors state this as an assumption: All customers are of the same class with the same consumption pattern.
    • The authors state this as an assumption: EV charging is an addition to the domestic load.
    • The authors state this as an assumption: An uncontrolled charging pattern is assumed for EV charging.
    • The authors state this as an assumption: If there is no violation during the critical peak period, there is likely no violation in other periods.
  • May combine two claims.

    Findingown data

    For single-phase voltage drop as PI, the hosting capacity with a 3.7 kW charger is 48% (10 customers) for the worst-case and 71% (15 customers) for the best-case scenario.

    “In Figure 14, the HC with a charging power of 3.7 kW, is 48% and 71% (10 and 15 customers) for the worst-case and best-case scenario, respectively, when voltage drop is the PI considered.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    The three-phase hosting capacity results show that 6-9 customers can charge their EVs simultaneously in the worst-case scenario without a violation, while 9-12 customers can connect their EVs at the same time in the best-case scenario.

    “The three-phase HC results show that 6-9 customers can charge their EVs simultaneously in the worst-case scenario without a violation, while 9-12 customers can connect their EVs at the same time in the best-case scenario.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    For single-phase equipment loading as PI, no customers can charge their EVs with an 11.5 kW charger during the worst-case scenario, while five customers can charge during the best case.

    “When considering equipment loading as the PI in Figure 15, none of the customers can charge their EVs with an 11.5 kW charger during the worst-case scenario, while five customers can charge during the best case.”
    • Also stated in: § 3.2.3. Hosting Capacity Estimation · plain
      “The HC is zero and five customers for the worst case and best case, respectively.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    The highest consumption in the studied grid occurred during the winter season, with 15 July 2021 being the critical day with the highest consumption.

    “It can be observed that the highest consumption occurred during the winter season, with 15 July 2021 being set as the critical day with the highest consumption, which is subsequently used as the simulated period for single-phase EV charging HC assessment.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    During the three-phase worst-case scenario, five and six customers can charge their EVs simultaneously for 85% and 60% of the year, respectively, without violating the limit of any PI.

    “Moreover, five and six customers can charge their EVs simultaneously for 85% and 60% of the year, respectively, during the worst-case scenario without violating the limit of any PI.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    During the three-phase best-case scenario, nine and 10 customers can be hosted simultaneously for 85% and 70% of the hours, respectively.

    “During the bestcase scenario, nine and 10 customers can be hosted simultaneously for 85% and 70% of the hours, respectively.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    The hosting capacity for three-phase EV charging is 5-8 EVs charging simultaneously for the worst-case scenario and 9-13 EVs for the best-case scenario.

    “The results show that the HC is 5-8 three-phase EVs charging simultaneously for the worst-case scenario and 9-13 EVs for the best-case scenario.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Each customer is capable of connecting only one EV to the grid.
    • The authors state this as an assumption: All customers are of the same class with the same consumption pattern.
    • The authors state this as an assumption: EV charging is an addition to the domestic load.
    • The authors state this as an assumption: An uncontrolled charging pattern is assumed for EV charging.
  • May combine two claims.

    Findingown data

    The hosting capacity of the balanced three-phase network is 5-8 customers for the worst-case scenario and 9-13 customers for the best-case scenario, considering all hours of the year and all performance indices.

    “The range of values for the hosting capacity of the balanced three-phase network obtained from the impact assessment conducted is 5-8 customers and 9-13 customers for the worst-case and best-case scenario, respectively.”
    • Also stated in: § 3.1.3. Hosting Capacity Estimation · hedged
      “This range is generally considering all hours of the year and all the performance indices.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning

    The results presented are for a specific grid, PI, and PI limits, and cannot be immediately transferred to another grid because distribution grids are non-homogenous.

    “However, the results presented are for a specific grid, PI, and the PI limits, and cannot be immediately transferred to another grid since the distribution grids are non-homogenous.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Distribution grids are non-homogenous.
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    In reality, there may be a higher probability of more EV charging simultaneously if the charging is distributed in time.

    “In reality, there may be a higher probability of more EV charging simultaneously if the charging is distributed in time.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning

    The approach of using uncontrolled EV charging without considering charging behavior and state of charge may underestimate the hosting capacity but generates a result that shows the variation in HC throughout the year.

    “This approach may underestimate the HC but generates a result that shows the variation in HC throughout the year.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisecitation

    Large-scale integration and simultaneous charging of multiple EVs can create power quality challenges and have a high impact on existing electrical networks, disrupting standard operating condition by creating technical challenges such as voltage violations, transformer and line overloading, and increasing electrical losses.

    “However, largescale integration and simultaneous charging of EVs can create power quality challenges for the distribution grid.”
    • Also stated in: § 1. Introduction · plain
      “However, large-scale integration and simultaneous charging of multiple EVs are identified as having a high impact on the existing electrical networks, disrupting the standard operating condition of the grid by creating several technical challenges, such as voltage violations, transformer and lines overloading, and increasing electrical losses [6].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [6] Ogunboyo, 2018, Effectiveness of Dynamic Voltage Restorer for Unbalance Voltage Mitigation and Voltage Profile Improvement in Secondary Distribution System, Can. J. Electr. Comput. Eng. source
  • Probably not a substantial claim: may not pass S4 (based).

    Premisereasoning

    High load variability will occur from the installation of higher power chargers because EV charging load ramps up and down over shorter periods.

    “However, since high load variability will occur from the installation of higher power chargers because the EV charging load will ramp up and down over shorter periods, it is important to consider key uncertainties like charging patterns and mode of charging in EV charging HC.”
    Quote in the paperNot a substantial claim
17 of 17
  • The paper relies on this without support.

    There is a dearth of studies on EV charging hosting capacity in the South African low-voltage distribution network.

    “Whereas there is an abundance of studies on solar photovoltaic (PV) HC, there is a dearth of studies on EV charging HC in the South African LV distribution network.”
  • The authors state this as an assumption.

    Each customer is capable of connecting only one EV to the grid.

    “It was assumed that each customer is capable of connecting only one EV to the grid.”
  • The authors state this as an assumption.

    All customers are of the same class with the same consumption pattern.

    “Since information about the load consumption of individual households is not available and all customers are assumed to be of the same class with the same consumption pattern, the load scaling method is applied to estimate the load for each consumer.”
  • The authors state this as an assumption.

    EV charging is an addition to the domestic load.

    “EV charging was considered an addition to the domestic load, and an uncontrolled charging pattern was assumed without considering the state of charge of the battery.”
  • The authors state this as an assumption.

    An uncontrolled charging pattern is assumed for EV charging.

    “EV charging was considered an addition to the domestic load, and an uncontrolled charging pattern was assumed without considering the state of charge of the battery.”
  • The paper relies on this without support.

    Utilities in South Africa have not yet specified the allowable EV chargers on the grid.

    “However, since utilities in South Africa have not yet specified the allowable EV chargers on the grid, other single-phase charging powers considered included 4.6, 5.75, 6.9, 9.2, and 11.5 kW chargers, corresponding to 20, 25, 30, 40, and 50-A fuses, respectively [22].”
  • The authors state this as an assumption.

    If there is no violation during the critical peak period, there is likely no violation in other periods.

    “Therefore, this period with the highest consumption throughout the year was chosen, and it was assumed that if there was no violation during this period, it was likely that there would not be in other periods.”
  • The paper relies on this without support.

    Distribution grids are non-homogenous.

    “since the distribution grids are non-homogenous”
8 of 8

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Abstract overstates best-case single-phase hosting capacity

    Major

    The abstract reports a best-case capacity of 15 EVs for the 3.7 kW charger. The results state that equipment loading limits this capacity to 10 customers when both performance indices are considered.

  • Conclusion gives incompatible three-phase hosting-capacity ranges

    Major

    The conclusion says 6-9 customers can charge without a violation in the worst case and 9-12 in the best case. The results give ranges of 5-8 and 9-13, respectively; they also state that a worst-case violation first occurs with six customers.

  • Abstract reverses the methods assigned to the two case studies

    Minor

    The abstract assigns the deterministic time-series method to single-phase charging and the stochastic method to three-phase charging. The methodology assigns them the other way around.

  • Figure 13a is assigned to both worst and best cases

    Minor

    The equipment-loading discussion calls Figure 13a the best-case scenario, but both its preceding sentence and the figure caption identify 13a as the worst case.

  • Results identify the network diagram as the hosting-capacity concept figure

    Minor

    The results refer to the 21-customer network as Figure 1, whereas the captions identify Figure 1 as the hosting-capacity concept and Figure 3 as the test network.

  • Conclusion treats a voltage-violation level as hosting capacity

    Minor

    The conclusion gives 76% as the upper end of the single-phase capacity when voltage drop is the performance index. The hosting-capacity results give a best-case maximum of 71% (15 customers) for the 3.7 kW charger; 76% is instead identified as the level at which a first violation occurs.

6 of 6

Cites

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Authors
Umoh, V., Adebiyi, A., & Moloi, K.
Affiliations
Durban University of Technology (ZA)
Corresponding author
Umoh, Vincent
Venue
Eng
Publisher
MDPI AG
Published
2023-07-12
Volume
4
Issue
3
Pages
1965-1980
ISSN
2673-4117 (ISSN-L)
OpenAlex
W4384131071
Cited by
12
References
21
Citations by year
2026: 4 · 2025: 3 · 2024: 3 · 2023: 2
FWCI
0.88
Type
journal article
Language
en
Open access
Locations
  • Eng—Advances in Engineering (publishedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
Durban University of Technology
Topics
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Electric Vehicles and Infrastructure
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Optimal Power Flow Distribution
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Smart Grid Energy Management
Keywords
hosting capacity, electric vehicle charging, low-voltage distribution networks, residential distribution networks, power quality, voltage drop, equipment loading, single-phase charging, seasonal variation, South Africa

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