---
title: "Electric optimization: what the Power Quality Rating means"
url: "https://3dfs.com/technology/electric-optimization"
description: "The Power Quality Rating scores how well a network's electricity does its work. Reactive and harmonic current pull it down. We take it off at the panel."
updated: "2026-10-15"
---

# Electric optimization: what the Power Quality Rating means

> The Power Quality Rating scores how well a network's electricity does its work. Reactive and harmonic current pull it down. We take it off at the panel.

The Power Quality Rating scores how well a network’s electricity does its work. Reactive and harmonic current pull it down. We take that current off the upstream path at the panel, and the rating rises.

Power Quality Rating, PQR, measures how efficiently electrical energy flows in a network, as a percentage from 0 to 100 [12](https://3dfs.com/technology/electric-optimization#src-12). It was introduced by 3DFS [14](https://3dfs.com/technology/electric-optimization#src-14). It is a company term, not an industry one. Electric optimization means raising it by taking the currents that do no work off the upstream path.

## What optimization is

A higher rating carries the same work on less current [13](https://3dfs.com/technology/electric-optimization#src-13). What comes back depends on the load mix. The site’s own meter settles it.

- Conductor heat. What a rating of 85% costs. A network at 0.85 power factor with clean waveforms rates 85% [12](https://3dfs.com/technology/electric-optimization#src-12). It draws 18% more current than at unity, and its conductor loss is 38% higher [1](https://3dfs.com/technology/electric-optimization#src-1).

- Transformer capacity. What raising the rating frees. At 0.85 power factor a 500 kVA transformer carries 263 kVAR of reactive power, and capacity comes back by the current removed [4](https://3dfs.com/technology/electric-optimization#src-4).

- Utility bill. Where the tariff bills kVA. A 100 kW load at 0.75 power factor needs 133 kVA, and at 0.99 it needs 101 kVA [5](https://3dfs.com/technology/electric-optimization#src-5).

- Server racks. Two racks, before and after correction. Power factor rose from 0.931 to 0.999 and from 0.831 to 0.995 [10](https://3dfs.com/technology/electric-optimization#src-10). Apparent power fell from 2,840 VA to 2,701 VA and from 1,898 VA to 1,655 VA [10](https://3dfs.com/technology/electric-optimization#src-10).

The rating scores each of the three phases, then averages them [12](https://3dfs.com/technology/electric-optimization#src-12). Each phase scores its displacement power factor, cos φ, divided by one distortion term for current and one for voltage [12](https://3dfs.com/technology/electric-optimization#src-12),[13](https://3dfs.com/technology/electric-optimization#src-13). Our PQR Simulator calls the result the true power factor [13](https://3dfs.com/technology/electric-optimization#src-13).

Issue by issue:

- Power factor. Reactive current lowers cos φ, and the score with it [12](https://3dfs.com/technology/electric-optimization#src-12).

- Harmonics. Current and voltage distortion divide the score down [12](https://3dfs.com/technology/electric-optimization#src-12).

- Voltage. Its distortion counts. Its level does not [12](https://3dfs.com/technology/electric-optimization#src-12).

- Phase balance and neutral current. One of the white paper’s four crucial power quality factors, with no term in its formula [12](https://3dfs.com/technology/electric-optimization#src-12). Our simulator adds a balance factor for unequal phase currents [13](https://3dfs.com/technology/electric-optimization#src-13).

- Impedance. Another of the four, also with no term in the formula [12](https://3dfs.com/technology/electric-optimization#src-12).

The root-mean-square (rms) current squared is the working current squared plus the reactive, harmonic and unbalanced currents squared [2](https://3dfs.com/technology/electric-optimization#src-2),[4](https://3dfs.com/technology/electric-optimization#src-4). Loss is the rms current squared times the resistance, so a 25% current distortion raises it 6.25%, and a 50% distortion raises it 25% [3](https://3dfs.com/technology/electric-optimization#src-3).

Two rules follow [4](https://3dfs.com/technology/electric-optimization#src-4). The removable share of the upstream load loss is 1 minus the power factor squared: 28% at 0.85, 44% at 0.75. The capacity freed on each upstream element is the rms current minus the working current.

With a clean voltage, a phase’s score is the working current over the hypotenuse [4](https://3dfs.com/technology/electric-optimization#src-4),[13](https://3dfs.com/technology/electric-optimization#src-13). Take the red square away and the hypotenuse shrinks to the working current. The difference is the capacity that comes back.

## What it costs

A rating of 85% from a 0.85 power factor on clean waveforms leaves 28% of the upstream load loss removable [4](https://3dfs.com/technology/electric-optimization#src-4),[12](https://3dfs.com/technology/electric-optimization#src-12). A 500 kVA transformer at nameplate and 0.85 power factor carries 263 kVAR of reactive power [4](https://3dfs.com/technology/electric-optimization#src-4). Remove that reactive current and 15% of its capacity comes back [4](https://3dfs.com/technology/electric-optimization#src-4). The plant pays for that headroom in a larger transformer or feeder, and each month where the tariff bills kVA [4](https://3dfs.com/technology/electric-optimization#src-4).

An illustrative trace, not a capture. At 0.85 power factor, 118 A carries the work of 100 A: 18% more current than at unity [1](https://3dfs.com/technology/electric-optimization#src-1).

A lower rating means more heat and stress on equipment [13](https://3dfs.com/technology/electric-optimization#src-13). A field study of two 1,000 kVA transformers found harmonic losses near 4% of the total in the first, at 20% distortion. In the second, at 40% to 50%, they were comparable to the fundamental losses. Filtering would have cut the second’s losses by 10,053 kWh a year, 45% of its total, and the first’s by 3% [6](https://3dfs.com/technology/electric-optimization#src-6). That is two transformers, not a rule.

The Department of Energy puts 2.5% voltage unbalance on a 100 hp motor at 9,517 kWh a year of added loss [7](https://3dfs.com/technology/electric-optimization#src-7). At US $0.08 a kWh, that is US $760 a year for that motor running 8,000 hours a year [7](https://3dfs.com/technology/electric-optimization#src-7).

An illustrative 60 Hz pair, not a capture. The uncorrected readout is the 0.85 power factor example [1](https://3dfs.com/technology/electric-optimization#src-1).

## How the industry has dealt with it

Capacity is bought. A larger transformer, a parallel feeder or a K-rated transformer for the harmonic heat makes room for the current the rating counts. None removes it. A K-13 transformer carries its nameplate rating under harmonic loads up to 75% of the total [8](https://3dfs.com/technology/electric-optimization#src-8).

Correction is bought one term at a time. A capacitor bank returns displacement capacity and has its own losses [9](https://3dfs.com/technology/electric-optimization#src-9). A tuned filter targets one harmonic order. Each lifts one term of the rating and leaves the rest. A bank steps within a fixed kVAR rating and a filter stays on one order [1](https://3dfs.com/technology/electric-optimization#src-1),[5](https://3dfs.com/technology/electric-optimization#src-5).

## How Software-Defined Electricity handles it

The panel is the last place the load currents meet before the feeder, so one device there can take them off the upstream path. The controller connects behind its own breaker, in parallel with the loads.

It corrects the current through the 23rd harmonic order, digitally and continuously, in place of one device per term [5](https://3dfs.com/technology/electric-optimization#src-5). It supplies the reactive, harmonic and unbalanced current locally, in under 5 microseconds [4](https://3dfs.com/technology/electric-optimization#src-4),[5](https://3dfs.com/technology/electric-optimization#src-5).

The source-side rms current falls toward the working current [4](https://3dfs.com/technology/electric-optimization#src-4). So the rating rises [12](https://3dfs.com/technology/electric-optimization#src-12). Where the tariff bills kVA, the 15-minute kVA demand falls with the reactive current. Our 2023 white paper states that networks rated 30% to 50% can reach 80% to 99% with Software-Defined Electricity [12](https://3dfs.com/technology/electric-optimization#src-12).

We assessed two server racks. Total current fell from 23.78 A to 22.60 A and from 15.86 A to 13.84 A [10](https://3dfs.com/technology/electric-optimization#src-10). A refrigerated container test recorded apparent power falling from 8,339 VA to 7,229 VA and average current from 9.73 A to 8.42 A [11](https://3dfs.com/technology/electric-optimization#src-11).

The controller runs at better than 96% round-trip efficiency at full load [5](https://3dfs.com/technology/electric-optimization#src-5).

## Where it matters

An [industrial plant](https://3dfs.com/solutions/industrial-manufacturing) buys its next expansion out of the headroom a low rating occupies. A [water plant](https://3dfs.com/solutions/water-wastewater) runs pumps at part load, where the reactive share is largest. A [data center](https://3dfs.com/solutions/data-centers-compute) counts capacity per rack.

Read more: [Consumption](https://3dfs.com/technology/consumption), where nonlinear loads produce waveform distortion. The [PQR Simulator](https://3dfs.com/technology/pqr-simulator) computes a rating and its cost in an educational model. [PQRA](https://3dfs.com/technology/pqra) scores a facility’s own recordings for cost and risk.

## What to measure

Prove the rating moved with a metered before-and-after under a measurement and verification protocol, on the same load over a billing window. On each phase, log the rating’s terms, power factor and the distortion of current and voltage, with kW, kVA, current and transformer temperature.

Expect apparent power, current and reactive power to fall in each pair. Expect the active power at the connection to include the controller’s own draw. Expect the branch circuits to carry the same current as before, so read the rating on the source side of the panel. The honest number is the rule, 1 minus PF² of the upstream loss, verified by the site’s own meter.

The corrector removes the load-driven share of the voltage drop and nothing else. The stated operating band is the product document’s [5](https://3dfs.com/technology/electric-optimization#src-5).

The rating, its formula and the 30% to 50% and 80% to 99% figures are ours [12](https://3dfs.com/technology/electric-optimization#src-12). The rating is not the efficiency of a motor, drive or server. It scores the electricity that feeds them. One number also hides which term moved: 85% can come from power factor, distortion or both [12](https://3dfs.com/technology/electric-optimization#src-12).

Without granular data, the return is hard to predict. Start by metering one transformer for a billing window before anyone quotes a box.

Sources

- 3DFS, The Hidden Cost of Poor Power Quality, white paper (January 2026), System Losses: 0.85 power factor needs 18% more current than unity and 39% more I²R loss. The 38% here is 1/0.85². First-party.

- MIT OCW 6.622, Lecture 4 (Perreault), p. 3.

- The Green Grid, White Paper 55, Table 4, p. 20.

- Rule review for this series: loss removable = 1 minus PF², capacity freed = I_rms minus I_active. First-party derivation.

- 3DFS, VectorQ Technical Overview (current revision), p. 12 and Technical Specifications table. First-party.

- León-Martínez et al., Environments 2023, 10(10), 177, Section 3, Tables 6 to 8. [https://doi.org/10.3390/environments10100177](https://doi.org/10.3390/environments10100177)

- U.S. Department of Energy, Motor Systems Tip Sheet 7, Eliminate Voltage Unbalance (2012).

- A leading maker’s application bulletin on harmonics in electrical systems, pp. 5-6.

- Girshin et al., Przegląd Elektrotechniczny 2021, 97(9), Eq. (3). [https://doi.org/10.15199/48.2021.09.23](https://doi.org/10.15199/48.2021.09.23)

- 3DFS, electrical network analysis of server racks at a data center, overview sheets. First-party.

- 3DFS, refrigerated container bench test, row 4d. First-party.

- 3DFS, Software-Defined Electricity: Optimized Electrification, Chapter 1, white paper (2023), p. 12. First-party.

- 3DFS, PQR Simulator (v0.5.8), method notes, metric 1, Power Quality Rating. First-party.

- 3DFS, Financial Benefits of Protecting Power Networks with Software-Defined Electricity, white paper (August 2018), p. 10. First-party.

Version 5.2