Power quality

EN 50160 as the statistical test it is — per ISO week and per phase — and the VDE-AR-N 4100 Unsymmetrieleistung of a customer installation.

EN 50160

Every limit is a share of 10-minute means over a window, not a threshold on one sample.

The standard is paywalled, so nothing is quoted: the figures are En50160Limits::LOW_VOLTAGE (Un = 230 V), each settable; other voltage levels are other values of the type. assess_en50160 reports per ISO week (Monday 00:00 Berlin, 167–169 hours) and per phase, never pooled.

use metering::grid::power_quality::{En50160Limits, En50160Verdict, PowerQualityInterval, assess_en50160};
use rust_decimal::dec;
use time::{Duration, macros::datetime};

// ISO week 23 of 2026: Monday 1 June 00:00 CEST is Sunday 22:00 UTC.
let start = datetime!(2026-05-31 22:00 UTC);
let mut week: Vec<PowerQualityInterval> = (0..1008)
    .map(|i| {
        let from = start + Duration::minutes(i * 10);
        PowerQualityInterval {
            voltage_l1_v: Some(dec!(231)),
            ..PowerQualityInterval::empty(from, from + Duration::minutes(10))
        }
    })
    .collect();
week[500].voltage_l1_v = Some(dec!(260)); // one sample over +10 %

let report = assess_en50160(&week, &En50160Limits::LOW_VOLTAGE);
let l1 = &report.weeks[0].phases[0];
assert_eq!(l1.voltage_band.compliant(), Some(true)); // 1 in 1 008 is within 5 %
assert_eq!(l1.voltage_absolute.compliant(), Some(false)); // +10 % admits none
assert_eq!(report.verdict(), En50160Verdict::NonCompliant);

• LimitOutcome::compliant() is None for an unmeasured parameter; the verdict is Unknown when a week is incomplete.
• worst is the sample furthest beyond the bound, not from nominal.
• PowerQualityInterval::voltage_out_of_range and friends are single-sample triage, not a conformance test.

Not assessed: voltage unbalance (u₂ = U₂ / U₁ needs phase angles), flicker, dips, swells, interruptions, harmonics by order.

Unsymmetrieleistung — VDE-AR-N 4100

VDE-AR-N 4100 Abschnitt 5.5.2 limits a customer installation's Unsymmetrieleistung to 4,6 kVA — VDE FNN Symmetrischer Anschluss und Betrieb in Kundenanlagen: "zur Einhaltung dieser Symmetriegrenze der Versorgungsspannung wurde bei einem Außenleiterstrom von 20 A ein Leistungsgrenzwert von 4,6 kVA festgelegt".

use metering::grid::power_quality::{Phase, PhaseApparentPower};
use rust_decimal::dec;

// A 22 kVA wallbox charging single-phase at 7,2 kVA breaches it.
let single = PhaseApparentPower::single_phase(Phase::L1, dec!(7.2));
assert!(!single.within_limit(None));
assert_eq!(single.excess_kva(None), dec!(2.6));

// Three 4,6 kVA units, one per Außenleiter: balanced.
let spread = PhaseApparentPower::default()
    .plus(Phase::L1, dec!(4.6))
    .and_then(|p| p.plus(Phase::L2, dec!(4.6)))
    .and_then(|p| p.plus(Phase::L3, dec!(4.6)))
    .unwrap();
assert_eq!(spread.unbalance_kva(), dec!(0.0));

• kVA, not kW.
• Device classes, not the grid meter: the rule applies "nur für Geräte die elektrische Energie einspeisen oder speichern können, also Erzeugungsanlagen, Speicher, Ladeeinrichtungen für Elektrofahrzeuge". Sum those per Außenleiter; a symmetric device contributes nothing (PhaseApparentPower::symmetric).
• 4,6 kVA is a parameter (UNSYMMETRIE_LIMIT_KVA); max − min is the arithmetic of the Hinweis's worked examples.