The main goal of the paper is to review the most important aspects of Professor’s Andrei Ţugulea power theory as they were formulated by its author in a series of articles and studies starting from mid 1980’s up to mid 1990’s. Also, the paper proposes to put in today’s perspective the main features and opportunities presented by this exceptional theory, by summarizing the most recent advances and developments in that field. Firstly, the essential characteristics of the power theory reside on the observation that unbalanced three-phase loads, energized from a supposedly symmetrical voltage system, pollutes the grid by reinjecting active power on the inverse and homopolar sequences, along with current harmonics. Secondly, a similar behavior was demonstrated for a nonlinear (distorting) three-phase consumer connected to a symmetrical power grid. These two components make up the core of Professor Ţugulea’s theory, which demonstrates that the existence of such a three-phase consumers (having both shortcomings) produces unnecessary active power circulation throughout the power grid with additional losses, including in energy billing overcharges for the balanced and linear consumers. More recently, efforts have been made to generalize the theory, initially formulated for an idealized power grid comprising a symmetrical ideal power generator, a linear balanced consumer and an unbalanced nonlinear load (The power line was supposed to be also linear and balanced). A general assessment of the opportunities offered by the theory in today’s electric energy consumption profiles and grid characteristics is performed and, finally, appropriate conclusions are drawn.

Keywords: Professor Ţugulea power theory, Professor Budeanu power theory, Three-phase circuits, Unbalanced load, Nonlinear (distorting) load, Symmetry active power, Non-symmetry active power, Residual (distortion) active power, Symmetry reactive power, Non-symmetry reactive power, Residual (distortion) reactive power, Circuit simulation, Power grid.