POWER QUALITY CHARACTERISTICS OF COMPUTER LOADS

Computer loads and systems can be found in all of society's industrial , commercial, and residential sectors, The nature of these loads is su ch that they distort the line-current waveforms and, in some cases, ca n significantly distort the supply-voltage waveforms causing disruptio n in computer system performance, The voltage (i.e., line-to-line, lin e-to-neutral and neutral-to-ground) and the phase current waveform cha racteristics of many computer loads are similar and reported in the li terature [1]-[6]. Some waveform patterns remain fairly stable during l oading cycles, while other vary significantly and randomly, This paper will present several case studies to reveal the unique power quality characteristics of several commonly used computer systems (e.g., works tations, heating plant process computers, and electron microscopes), T he dominant even- and odd-harmonic components of the waveforms will be presented and discussed in some detail. This paper will also discuss the impact of the computer loads on the supply voltage waveforms.