Harmonic Filter Design for Hvdc Lines Using Matlab

I INTRODUCTION Advancement in technology of semiconductor devices has led to a revolution in electronic technology over the past decade. However rise in the power quality (PQ) problem is due to power equipments which include adjustable-speed motor drives (ASDs), electronic power supplies, direct current (DC) motor drives, battery chargers, electronic ballasts. The distortion in current is due to the nonlinearity of the resistor. The nonlinear loads are constructed by nonlinear devices, in which the current is not proportional to the applied voltage. The concept of current distortion is illustrated in the figure 1.In figure 1 a sinusoidal voltage is applied to a simple nonlinear resistor in which the voltage and current vary according to the curve shown. From figure 1 we observe, the voltage is perfectly sinusoidal, the resulting current is distorted. The Non-linear loads seem to be the main source of harmonic distortion in a power distribution system. The Non-linear loads produce harmonic currents and inject it into the power distribution network at the point of common coupling (PCC).These harmonic current can interact negatively with a broad range of power systems equipment such as transformers, motors and produce more losses, overheating and overloading. II SOLUTIONS FOR HARMONIC DISTORTION PROBLEMS There are set of conventional solutions to the harmonic distortions which have existed for a long time. Some of them are as follows 1) The passive filtering is the simplest conventional solution to mitigate the harmonic distortion. The passive filtering mechanisms do not depend upon an external power supply. Although simple, the use of passive elements does not respond correctly to the dynamics of the power distribution systems. Also the use of passive elements at high power level makes the filter heavy and bulky. The passive filters are known to cause resonance, thus affecting the stability of the power distribution systems. 2) The active power filter (APF) provides solution for harmonic distortion mitigation. The active filters are made of passive and active components and require an external power source. The APF utilize power electronics technologies to produce current components that ABSTRACT: This paper presents harmonic filter design for HVDC lines using MATLAB version R2009a.Non-linear devices such as power electronics converters can inject harmonics alternating currents (AC) in the electrical power system. The number of sensitive loads that require ideal sinusoidal supply voltage for their proper operation has been increasing. To maintain the quality limits proposed by standards to protect the …