Analysis of power system harmonics and their elimination using filters /

Abstract

The modern electric power systems that include non-linear loads may experience power quality problem such as harmonic distortion. Non-linear loads draw current that passes through all of the impedances between the loads and the system sources. The current causes power quality problems. This thesis investigates the use of harmonic elimination methods to evaluate and improve harmonic distortion in the system. Computer simulation is used to determine the location S-=- of the harmonics and the amount of the harmonic distortions. The results of the simulation are used to design filters for the various load locations and buses to improve power quality. Short circuit ratio (SCR) at the point of common coupling (PCC) is to determine the current distortion limit (IEEE-519, 1992). The filters are applied to keep the total harmonic distortion (THO) of the current and the voltage within the limits set by the IEEE Recommended Practices and Requirements for Harmonic Control in electrical power systems. For best result, filters are installed close to the non-linear loads. The application of the filters at the non-linear load locations reduce the total harmonic distortions of the voltage below 5 percent and the total harmonic distortions of the current below 15 percent. These limits meet the IEEE-519, 1992 limit.