Abstract
The penetration of nonlinear loads within the commercial and residential sectors can cause severe problems to power systems including an increase in voltage distortion, thermal effects on rotating machines, a decrease in power factor, impact on energy metering and a decrease in the overall system efficiency. In order to precisely assess their effects on power systems, Personal Computers (PCs) were monitored and harmonic indices were measured. Curve fitting technique is then used to formulate the mathematical relationships between the harmonics generated from the PCs versus different system conditions including the variations of source voltage, impedance, frequency and background voltage distortion. Practical variations of these parameters were considered.