ABSTRACT
In this chapter, the fundamental load compensation techniques for unbalanced linear loads such as resistance, inductance, capacitance, and their combinations are discussed. The main objective here is to maintain source currents balanced sinusoidal and in-phase with their respective phase voltages to achieve a unity power factor. From the study, it is inferred that a compensator can function independently, either as a load compensator or as a voltage regulator. Various stages of compensator currents are realized using, sampling and averaging techniques and expressions for compensator susceptances are developed in terms of load currents at specified phase voltages. It is found that for a delta-connected load or a three-phase ungrounded system, it is always possible to design a compensator comprised of purely reactive elements such as inductance and capacitance to draw source currents which are balanced sinusoids at the fundamental frequency and in-phase with the utility voltages. This is not true for a three-phase grounded system as it involves a real power requirement from the compensator in some phases. A number of examples are presented to illustrate the concepts.
