LV 住宅ネットワークにおける EV の充電と電力品質 — 個別の充電器から車両の普及まで
| Charger type modelled | レベル 2 on-board charger — 7.2 キロワット, 単相, household installation |
| 方法論 | Probabilistic model from measured harmonic spectra — Gaussian Mixture Models — validated against real charger measurements |
| Simulation tool | OpenDSS — time-series harmonic power flows at 10-minute resolution |
| Uncertainty modelling | Monte Carlo simulation — variable start charge time, connection state-of-charge, EV location on feeder |
| Dominant harmonic | 3rd harmonic — most intense throughout the charge cycle regardless of penetration level |
| 重要な発見 | Voltage unbalance and network chargeability both increase with EV penetration level — the third harmonic is the primary driver |
| Supraharmonic issue | |
| Critical threshold | Uncontrolled simultaneous residential charging at high penetration levels can push VUF beyond the 2% IN 50160 limit at feeder end buses |
01 Context — The Scale of the Problem
The electrification of road transport is now a policy commitment in most OECD countries, with targets ranging from 30% へ 100% EV market share by 2030–2040 in Europe, 北米, and Asia-Pacific. The PQ implications of this transition — in terms of harmonics, 電圧不平衡, and supraharmonic emissions on residential LV distribution networks — have been studied extensively in isolation, but the combined picture at the feeder level, accounting for the stochastic nature of charging behaviour, has been harder to quantify.
ザ 2021 study by Torres et al. in Applied Energy addresses this gap directly. Starting from measured harmonic spectra of a real Level 2 on-board charger, they built a probabilistic model capturing the charger’s non-linear behaviour across the full charge cycle — from initial connection at a high state of charge deficit through to completion — and then deployed this model in Monte Carlo simulations on an OpenDSS residential LV feeder to assess PQ impacts across multiple EV penetration scenarios.
レベル 1 charging (1.4–1.9 kW, standard household outlet) produces modest harmonic currents that are easily absorbed by the distribution network. レベル 2 charging at 7.2 kW — roughly 4–5 times the power — produces proportionally larger harmonic currents that can saturate the neutral conductor, cause significant third harmonic voltage distortion on the feeder, and contribute to voltage unbalance when distributed unevenly across the three phases. As Level 2 home charging becomes the default for EV owners who park overnight, the transition from Level 1 to Level 2 as the primary residential charging mode represents a step change in the PQ impact on LV distribution networks.
02 The Level 2 Charger as a Non-Linear Load
A Level 2 EV charger is a power electronic converter — specifically a single-phase AC/DC rectifier with power factor correction (PFC) circuitry — that draws current from the grid in a controlled, non-sinusoidal pattern. The harmonic current profile of an EV charger is not constant: it changes throughout the charge cycle as the battery voltage rises and the charger’s control algorithm adjusts the current draw to manage the state of charge transition.
Probabilistic harmonic spectra
Torres et al. characterised the harmonic spectra of a real Level 2 charger across its full charge cycle using laboratory measurements. The key finding was that the harmonic spectra exhibit irregular, probabilistic behaviour — they are not deterministic values that can be represented by a single table of harmonic orders and magnitudes. The charge state of the battery, the grid voltage waveform shape at the moment of connection, and the charger’s internal control state all influence the harmonic spectrum. This is why simplified, EV 充電器の決定論的高調波モデル - 現在でも計画ツールで広く使用されている - フィーダ レベルで実際の PQ への影響を体系的に過小評価する.
この研究では、混合ガウス モデルを使用してこの確率的動作を表現しました。 (GMM) 測定されたスペクトルに適合 — 平均高調波成分と接続状態間のその変動性の両方を捕捉. その後、GMM モデルがモンテカルロ シミュレーション フレームワークに埋め込まれ、高調波の不確実性がフィーダレベルの PQ 評価に伝播されました。.
広範なEV充電器の文献で確認されている微妙な点は、EV充電器の高調波放射は、接続されている系統電圧から独立していないということです。. When the LV feeder already contains third harmonic voltage distortion — the “flattened sinusoid” that is typical of residential grids with multiple switch-mode power supplies — this distorted voltage changes the charger’s operating point and can modify some harmonic components by 30–300% compared to what would be measured on a clean sinusoidal supply. This bidirectional coupling means that as EV penetration increases and third harmonic distortion worsens, the charger emissions themselves change — a positive feedback loop that is not captured in standard harmonic superposition models.
03 Third Harmonic Dominance — The Neutral Conductor Problem
Across all penetration levels and all charge cycle states examined in the Torres et al. study, the third harmonic (150 Hz at 50 Hzのシステム) was consistently the most intense harmonic component in the EV charger current. This is not specific to EV chargers — it is a characteristic of all single-phase switch-mode power supplies, including laptop chargers, LED drivers, and the switched-mode power supplies used in all modern consumer electronics. EV chargers simply add a much larger magnitude of third harmonic current to a network already dominated by triplen harmonics from these smaller loads.
Why triplen harmonics are uniquely dangerous
In a balanced three-phase four-wire system, positive and negative sequence harmonic currents (5番目の, 7番目の, 11番目の, 13番目の…) cancel in the neutral conductor — the neutral carries near-zero current. Triplen harmonics (3RD, 9番目の, 15番目の…) ゼロシーケンスです - これらはすべての 3 相導体で同相であるため、中性線で算術的に加算されます。. 3 つの単相 EV 充電器 (各相に 1 つ) を備えた完全にバランスのとれた三相システム, 同一の充電器, 同一の充電状態 — 正相中性線電流はゼロですが、第 3 高調波における中性点電流は第 3 高調波相電流の 3 倍に等しくなります。.
実際的な結果は、住宅用 LV ネットワーク内の配電変圧器と中性線が、接続された負荷の基本電流需要に合わせてサイズ設定されたということです。, 通常の不均衡に対する熱マージンあり. 高密度単相 EV 充電の導入により、既存の LV インフラストラクチャの設計想定を完全に超えた 3 倍高調波による系統的な中性過負荷が発生します。.
04 浸透レベル — フィーダーエンド効果
Torres らによるモンテカルロ シミュレーションの結果. すべての侵入シナリオにわたって一貫した空間パターンを実証する: EV の充電は、フィーダの開始時の電圧品質にほとんど影響しません。 (配電変圧器の近く) しかし、電圧の不均衡が限界を超える可能性があります。 2% IN 50160 中程度の普及レベルであってもフィーダーエンドバスでの制限. これはスケールでのインピーダンスの議論です - 変圧器から遠ざかるほど, フィーダのインピーダンスが高いほど, 特定の高調波電流が電圧歪みに変換されると、.
| EV普及レベル | フィーダー起動時の効果 | フィーダー端での影響 | 3三次高調波電圧 | VUF リスク |
|---|---|---|---|---|
| 低い (<10%) | 無視できる | VUFのわずかな増加 | 制限内で | 低い |
| 中くらい (10–30%) | 無視できる | 検出可能なVUFの増加 | 限界に近づいている | 適度 |
| 高い (>30%) — 制御されていない | わずかな歪み | VUF を超える可能性があります 2% | 限界を超えている可能性が高い | 高い |
| 高い (>30%) — スマート充電 | 無視できる | VUF制御 | 制限内で | 低い |
高い浸透力, 制御されていない充電シナリオ（EV 所有者が帰宅後すぐにプラグを差し込み、最大レートで充電する）は、最悪の PQ 状態を表しており、また、, 使用時間に応じた料金設定やスマートな充電義務がない場合, EVユーザーの自然な行動. に 30%+ 住宅用フィーダーへの侵入, 夜間の同時充電により、既存の住宅のピーク負荷よりも大きなピーク需要イベントが発生します, 既存のピークと正確に同時に発生します, そして、フィーダのインピーダンスがフィーダ端での電圧歪みに変換される 3 次高調波成分が導入されます。. これは将来の送電網計画における理論上のリスクではありません。ノルウェーのEV密度の高い住宅地ではすでに起こっています。, オランダ, そしてカリフォルニア.
05 Supraharmonics — The Hidden EV Charger Emission
Beyond the classical harmonic range (まで 2 kHzの), EV chargers produce supraharmonic emissions in the 2–150 kHz range from their high-frequency PWM switching stages. These emissions are distinct from the classical harmonics addressed by IEC 61000-3-2 and are not currently subject to specific emission limits in the distribution network context.
The interaction between EV charger supraharmonic emissions and the grid network creates two specific problems:
- PLC communication interference — Smart metering, デマンドレスポンス, and EV charging management systems often use power line carrier frequencies in the 9–95 kHz range (CENELEC bands). EV charger switching frequencies can fall directly in these bands, disrupting the communication signals that are intended to manage the EV charging itself — a circular interference problem
- Intermodulation with other devices — When multiple EV chargers with slightly different switching frequencies are connected to the same feeder, intermodulation products appear at sum and difference frequencies — as demonstrated in the CS06 supraharmonics case study. These additional frequency components can interfere with equipment not designed to tolerate this frequency range
- Grid voltage feedback on harmonic emission — The existing third harmonic voltage distortion on residential feeders (from switch-mode power supplies) modifies the EV charger’s operating point, changing its harmonic emissions by up to 30–300% compared to laboratory measurements on clean supplies. This means field measurements at high-density EV installations will differ significantly from type-test measurements on individual chargers
The most effective mitigation for EV-related PQ problems at the feeder level is smart charging — coordinating charge start times, rates, and phase allocation across multiple EVs to avoid coincident peak demand and uneven phase loading. Optimised smart charging can eliminate VUF exceedances at the feeder end that would otherwise occur under uncontrolled charging at the same penetration level, without requiring any hardware mitigation at individual charger or feeder level. Phase-balancing allocation — assigning new single-phase charger connections to whichever phase has the most spare capacity — is the simplest form of smart charging with the highest benefit-to-cost ratio.
06 電力品質の観点
The EV charging PQ problem has a specific character that distinguishes it from historical PQ problems: it is a planning problem as much as an engineering problem. Arc furnaces and VFDs are installed by industrial customers who engage with the utility during the connection process — there is a defined point at which PQ assessment happens and mitigation is negotiated. Residential EV chargers are installed by homeowners who connect to whatever outlet is available, at no notice to the distribution network operator, at rates that can double overnight if an incentive programme launches.
The third harmonic dominance finding is immediately useful for distribution engineers assessing existing infrastructure. Neutral conductors in older residential LV networks — particularly those built in the 1960s and 1970s — were sized for the unbalance currents expected from conventional single-phase residential loads, not for the triplen harmonic currents from EV chargers. A neutral conductor that is thermally adequate for 20% residential load unbalance may be significantly overloaded by the triplen harmonic neutral current from 15–20% EV penetration on a feeder end bus.
The practical utility response to EV charging PQ is not primarily technical mitigation — it is data collection. The key unknown for any distribution network is the actual EV penetration on each LV feeder in real time, and the phase distribution of those chargers. A utility that knows which customers on which feeders have EV chargers — and on which phase each charger is connected — has the information needed to identify feeder-end VUF risk before it manifests as a complaint. Without this data, the utility is flying blind. Smart meter data, combined with the probabilistic modelling methodology demonstrated by Torres et al., provides the analytical foundation for proactive LV feeder PQ management in the EV era.
参照
- Torres S, Durán I, Marulanda A, Pavas A, Quirós-Tortós J. “電気自動車と低電圧ネットワークの電力品質: 実際のデータの分析とモデリング。” 応用エネルギー, 2021. DOI: 10.1016/j.apenergy.2021.117718
- イクバル MN 他. “プラグイン電気自動車充電器の高調波および超高調波放射。” スマートシティ, フライト. 5, しない. 2, PP. 496–524, 2022. DOI: 10.3390/スマートシティ5020027 — オープンアクセス CC BY 4.0.
- ウルハクAら. “電気自動車の充電が都市配電網の電圧不平衡に与える影響。” インテリジェント産業システム, フライト. 1, PP. 51–60, 2015.
- IN 50160:2010+A3:2019. 公共電力網から供給される電力の電圧特性. CENELEC, ブリュッセル.
- IEC 61000-3-2:2018. 電磁両立性 - パート 3-2: 高調波電流エミッションの制限. IEC, ジュネーブ.
- IEC 61000-2-2:2002+AMD1:2017. 電磁適合性 — 公共の LV 供給システムにおける低周波伝導妨害に対する適合性レベル. IEC, ジュネーブ.
Primary source: Torres S, Durán I, Marulanda A, Pavas A, Quirós-Tortós J. “電気自動車と低電圧ネットワークの電力品質: 実際のデータの分析とモデリング。” 応用エネルギー, 2021. DOI: 10.1016/j.apenergy.2021.117718. 参考となる参考文献: イクバル MN ら。, “プラグイン電気自動車充電器の高調波および超高調波放射,” スマートシティ, 2022, CCBY 4.0.
このケーススタディは、教育目的のために概要と解説の形で提示されています。. SVG 図と PQ パースペクティブ セクション (セクション 6) Denis Ruest によるオリジナルの IPQDF 編集コンテンツです, 修士号. (適用済み), P.Eng. (レット。). IPQDF は元の研究の著者であることを主張していません.