Spectral analysis of instantaneous powers in single-phase and three-phase systems with use of p-q-r theory

Instantaneous active power p, q-axis instantaneous reactive power q, and r-axis instantaneous reactive power q, have been defined as linearly independent of each others in the time domain in three-phase four-wire systems with the use of p-q-r theory. This paper renames the instantaneous active/reactive powers as instantaneous real/imaginary powers to distinguish them from the traditional definition of active/reactive powers. The instantaneous real/imaginary powers are analyzed at various circuit conditions in single-phase and three-phase systems. The q-axis instantaneous imaginary power q/sub q/, is orthogonal to the other two instantaneous powers p and q,. in the frequency domain. By analyzing the spectral distribution of the instantaneous powers p, q/sub q/, q, this paper proposes unified definitions for some power quality factors which can evaluate and identify the various circuit conditions both for single-phase and three-phase systems.

[1]  L. Czarnecki.  Reactive and unbalanced currents compensation in three-phase asymmetrical circuits under nonsinusoidal conditions , 1989 .

[2]  Alessandro Ferrero,et al.  Current decomposition in asymmetrical, unbalanced three-phase systems under nonsinusoidal conditions , 1994 .

[3]  Fang Zheng Peng,et al.  Reactive power and harmonic compensation based on the generalized instantaneous reactive power theory for three-phase power systems , 1996 .

[4]  D. Sharon.  Reactive-power definitions and power-factor improvement in nonlinear systems , 1974 .

[5]  L. Czarnecki.  What is wrong with the Budeanu concept of reactive and distortion power and why it should be abandoned , 1987, IEEE Transactions on Instrumentation and Measurement.

[6]  Hirotami Nakano,et al.  Reactive Power Compensation based on An Novel Cross Vector Theory , 1994 .

[7]  Hirofumi Akagi,et al.  The instantaneous power theory on the rotating p-q-r reference frames , 1999, Proceedings of the IEEE 1999 International Conference on Power Electronics and Drive Systems. PEDS'99 (Cat. No.99TH8475).

[8]  Alessandro Ferrero,et al.  A new approach to the definition of power components in three-phase systems under nonsinusoidal conditions , 1991 .

[9]  A. E. Emanuel.  The Buchholz-Goodhue apparent power definition: the practical approach for nonsinusoidal and unbalanced systems , 1998 .

[10]  W.J.M. Moore,et al.  On the Definition of Reactive Power Under Non-Sinusoidal Conditions , 1980, IEEE Transactions on Power Apparatus and Systems.