THE EFFECT OF PASSIVE FILTER ON 3RD, 5TH AND 7TH HARMONICS IN NON-LINEAR LOAD.

Development of technologies has caused electricity to be one of the vital necessity not only for industrialization but also commercial and domestic usage. The increase in application of nonlinear loads such as power electronic devices either in industry or domestic appliances, has caused power distortion in the voltage and current waveform at rated magnitude and frequency, also known as harmonics. Harmonics results in overheating of transformers, motor and cables and logic faults of digital devices. This increase in power quality disturbances has led to development of various optimization techniques and filter designs. This report discusses on the problems caused by harmonics in electrical networks and discusses on the previous research works done to mitigate harmonics especially via passive filters, namely single tuned passive filter. The objective of this project is to conduct the analysis on the harmonics caused due to the application of nonlinear load and propose the design of the passive filter that is able to further mitigate the 3rd, 5th and 7th harmonics. The passive filters that is considered in this report is the single-tuned passive filter due to its high quality factor that provides maximum attenuation for one harmonic. In the design of this filter, the passive elements such as the capacitor, inductor and resistor are identified and derived and a modification is introduced to the filter to increase the efficiency of harmonics mitigation. A fixed nonlinear load is simulated with the single-tuned passive filter in MATLAB/Simulink environment. The investigation of harmonics has been carried out via Fast Fourier Transform (FFT) analysis to evaluate the Total Harmonic Distortion (THD) of the nonlinear load with and without filter application. The MATLAB/SIMULINK software has been employed for presenting the simulation results because it is well established and the recognized simulation software for power systems.