Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Electrical and Computer Engineering

First Advisor

Leszek S. Czarnecki


This dissertation explores a new method of adaptive compensation and harmonic suppression in distribution systems. The compensator under development and investigation integrates a harmonic blocking compensator (HBC) with an adaptive balancing compensator (ABC) resulting in an adaptive harmonic blocking compensator (AHBC). Such a compensator can be used for compensating reactive power, for symmetrizing supply currents, for protecting the distribution system against load generated current harmonics and, consequently, the voltage harmonic distortion caused by non-linear loads. Harmonic blocking compensators are designed for compensating fixed loads, and they are not adaptive devices, while the adaptive capability of compensators is becoming more and more important. This dissertation investigates the possibility of the conversion of a HBC into an adaptive device. A HBC and an ABC are combined to form a new device which is referred to as an "adaptive harmonic blocking compensator." A HBC provides the harmonic suppression. An ABC which contains three thyristor controlled susceptance circuits provides the variable susceptances needed for reactive and unbalanced power compensation. A digital signal processing system (DSPS) for three-phase quantities has been developed for the AHBC control. This DSPS consists of signal processing hardware and a control algorithm. The hardware includes transducers, a microcontroller and some associated circuits for signal processing. The control algorithm provides the thyristor firing angles calculated based on the current orthogonal decomposition method. The dissertation presents the fundamentals of AHBC operation and design, results of computer modeling using PSpice and experimental results obtained from a laboratory prototype.