Limits of Harmonic Power Recovery by Power Quality Conditioners in Three-Phase Three-Wire Systems Under Non-sinusoidal Conditions

Power quality conditioners were originally meant to provide protection to electrical loads connected to the power system against power quality disturbances. Such protection feature brings mostly intangible benefits that are difficult to quantify in monetary terms. This is the reason why some providers of power quality solutions focus more on promote energy savings benefits rather than emphasize the protection feature at the time of advertising their products. Sometimes, the energy savings are exaggerated and inflated with the aim to present a more convincing argument to the customers about why they should acquire a particular solution. This technical paper present presents two formulas that determine the theoretical maximum energy savings that can be achieved when a power quality conditioner targets current harmonics within an industrial facility. In particular, the formulas predict the maximum amount of harmonic active power that can be recovered by power quality conditioners (e.g. harmonic active power filter) in a three-wire three-phase system that contains linear and nonlinear loads. The upper bound of the harmonic active power is the total harmonic apparent power. The upper bound is given in function of the Total Harmonic Distortion of the current and the voltage measured at the point of common coupling and total apparent power of the loads.