Category Archives: Energy Efficency Lighting

Electric Power Quality and Lighting (part 2)

Posted May 29 2012 by Sufi Shah Hamid Jalali in Energy Efficiency, Lighting on Electrical Engineering Portal

Original Source: Wolsey, Robert, Power Quality, Volume 2, Number 2, February 1995 (Lighting Research Center (LRC) and Power Quality),

What is power factor?

Power factor is a measure of how effectively a device converts input current and voltage into useful electric power. Mathematically it is defined as follows:power-factor-triangle-explained

Power factor triangle

power-factor-formula

 

 

Where P is active power and S is the apparent power.

It is often confused with: Continue reading →

Electric Power Quality and Lighting (part 1)

Posted May 26 2012 by Sufi Shah Hamid Jalali in Energy Efficiency, Lighting with 2 Comments
on Electrical Engineering Portal
Original Source: Wolsey, Robert, Power Quality, Volume 2, Number 2, February 1995 (Lighting Research Center (LRC) and Power Quality)

Introduction

Concerns about the effects of lighting products on power distribution systems have focused attention on power quality. Poor power quality can waste energy and the capacity of an electrical system; it can harm both the electrical distribution system and devices operating on the system.

There are many elements in a power system that affects two major parameters; power factor and harmonics. Electric motors, some lighting fixtures, transformers and other inductive and capacitive appliances introduce reactive power to the system, and thus involved in damaging the power factor. These components need reactive power to work.

Nonlinear loads like UPS, computer systems, fluorescent fixtures, CFLs, digital electronics, etc. are distorting current waveforms and introducing harmonics to the power system.

This technical article will help lighting specifiers and consumers better understand power quality, so that they can more confidently select energy-efficient lighting products. Continue reading →