Unbalance Compensator for Three-Phase Industrial Installations

This paper describes constitution, design and operation of a passive unbalance compensator for variable loads in three-phase industrial installations. Compensator is integrated by three-phase connections of variable coils and capacitors. Values of those elements, and thus unbalance power delivered by the compensator, can be changed by switches commanded by an electronic control circuit. An important compensator design parameter introduced in this paper is the power of the unbalance step since it defines composition and values of the elements of the unbalance step, which is the basic three-phase connection of inductances and capacitances in the compensator. Because unbalances in power systems are caused by active and reactive loads, two unbalance steps have been defined: active and reactive, however, power of the unbalance compensator does not depend on the total active and reactive powers, but the differences between their values in each phase of the load.