Power factor
Power Factor Penalty Explained, and How to Reduce It
A power factor penalty bills the reactive power your site draws. The three tariff mechanisms behind it, what a low power factor costs, and how to reduce the penalty.
Subject area
Power Factor and Power Quality
Reactive power does no useful work and still has to be carried by the wires, which is why utilities bill for it. A low power factor shows up as an explicit penalty line, as a kVA-based demand charge, or as a multiplier applied to billed kilowatts, depending on the tariff — and the three are not equivalent, so a correction that pays back on one schedule may not on another. This section covers the power triangle, how to read a power factor penalty clause, capacitor bank sizing and the harmonic risks that come with it, active correction, and how variable frequency drives interact with displacement power factor. Also here: voltage level discounts, transformer ownership credits, and what primary metering changes on the bill.
Start here
The piece that carries the subject. Read this one first.
Supporting analysis
Everything underneath the pillar, in this subject area.
Power factor
Harmonics, Resonance and Why Capacitors Sometimes Make It Worse
Adding capacitance to a system full of drives can create a resonant circuit that amplifies the very currents it was meant to be indifferent to. Check before you order.
Power factor
Sizing a Capacitor Bank
The calculation is short and the target is not maximum correction. Sizing to land inside a band, with the harmonic environment checked first, is what separates a working installation from a failure.
Power factor
Variable Frequency Drives and Displacement Power Factor
Drives are frequently sold as improving power factor, and in one sense they do. The sense that matters for your bill depends on which power factor your meter measures.
Power factor
Voltage Level Discounts and Primary Metering
Taking service at a higher voltage and owning your own transformer moves cost from the utility to you, and tariffs pay for that with a discount. Whether it is worth it is arithmetic.
Power factor