Estimating the Power Quality disturbance caused by Personnel Computer

Personal computers draw non-sinusoidal current with odd harmonics more significantly. Power Quality of distribution networks is severely affected due to the flow of these generated harmonics during the operation of electronic loads. Switch-mode power supplies (SMPS) are one of the most vital part of PC, typically found in large numbers in modern power supply systems. These devices usually draw non-linear current and are, therefore, significant sources of harmonics. Although it is well known that the presence of harmonics will result in negative effects (e.g. higher thermal stresses and overloading, or increased neutral conductor currents), the assessment of the actual harmonic levels is not a simple task. Harmonic emission of individual SMPS will vary based on the differences in their circuits and operating conditions. As a consequence, these variations result in the harmonic emission of the harmonics, which is analysed in detail in this paper. Validation of the load models is done by performing case study for an industrial supply system and comparing the THDs obtained from simulation using MATLAB with the THD values obtained by measurement.