Harmonic distortion and reactive power compensation in single phase power systems using orthogonal transformation technique

This paper reports a novel strategy for analysing a single phase power system feeding a non-linear load. This strategy is based on a new theory to transform the traditional single phase power system into an equivalent two-axis orthogonal system. This system is based on complementing the single phase system with a fictitious second phase so that both of the two phases generate an orthogonal power system. This would yield a power system which is analogous to the three phase power system but with the phase shift between successive phases equal to pi/2 instead of 2pi/3. Application of this novel approach makes it possible to use the complex or Gauss domain analytical method in a similar way to the well known method of instantaneous reactive power for three phase power system instigated by Akagi et al in 1983. Thus, for the fictitious two-axis phase power system, the concept of instantaneous active and reactive power could be instigated. Moreover, the concept of instantaneous power factor could be defined. The novel strategy of power system analysis outlined in this paper is applied to a single phase power system feeding a non-linear load in conjunction with an active power filter. The latter serves the purpose of compensating for either of the instantaneous reactive power or the harmonic current distortion in the single phase power system under investigation or for compensating of both. Experimental results demonstrated the effectiveness of the novel single phase power system analysis reported in this paper.