Present point of view about the instanta

The instantaneous reactive power theory has been predominantly employed for nonlinear load compensation using active power filters (APF). This study aims to evaluate its effectiveness in APF control, particularly in yielding constant source power post-compensation in a straightforward manner. The methodology involves analyzing the theory's performance with balanced sinusoidal source voltages as well as with unbalanced or non-sinusoidal conditions. While the p-q theory provides constant source power under various circumstances, it tends to yield unbalanced and non-sinusoidal source currents in non-ideal cases. The paper discusses necessary adjustments to the original theory to enhance its applicability across varying voltage supply scenarios, including a reformulation in phase coordinates to facilitate the analysis of diverse compensation strategies. Furthermore, the incorporation of instantaneous imaginary power is shown to refine the p-q formulation into a comprehensive theory of electric power for three-phase systems. Practical applications of these compensation strategies are explored within a real-world power system context, and the corresponding results are documented.