Active power, power factor and harmonics
Energy costs and electrical design require different indicators.
Active power in watts describes power actually converted. Apparent power in volt-amperes is the product of voltage and current. Their ratio is power factor. Distorted current waveforms can also matter with electronic equipment; a displacement cos-phi value alone does not always describe the complete situation.
A lighting energy balance uses active power and operating time. Cable loading, supply design and the combined effect of many loads require additional information. THD describes harmonic distortion and is not the same quantity as power factor.
Compare figures under equivalent conditions. A driver may behave differently at low dimming levels than at rated output. Relevant operating states should therefore be covered by data sheets or suitable measurements. Assessment of the wider electrical installation and any corrective measures belongs with a qualified electrical designer.
What to clarify for your project
- Use active power for energy estimates.
- Do not equate power factor with THD.
- Include planned dimming conditions in electrical design.
Remember: Match the indicator to the question: consumption, current loading or power quality.