Reactive power control for Unbalanced Load

Abstract: An unbalanced three-phase load may be transformed into balanced load by the implementation of the reactive compensator. The balanced operation of the three-phase load requires an unbalanced reactive compensator, by that more amount of harmonics are generated. A three- phase reactive compensator includes thyristor- controlled reactors and switched capacitors is developed in this paper to evaluate the optimum values of reactive volt- amperes generated by the compensator. The calculations of reactive volt- amperes are based on the fact that the addition or subtraction of the same volt-amperes for three brunches of unbalanced TCR does not change the balanced operation of the load, but can modulate the amount of harmonics generated by the reactive compensator. This balanced-change in volt-amperes of TCR can be equalized by the three-phase thyristor-switched capacitor (TSC). Different sets of firing angles for thyistors are determined. All sets of firing angles balance the load and generate different amount of harmonics. Optimum values of firing angles required for a balance load and minimum generation of harmonics were defined