Technique to calculate total harmonic distortion of phase current in a three-phase power system
In this paper, a technique to calculate the total harmonic distortion of the line current in a three-phase power system is proposed. This technique uses mathematical equations describing a transition to a synchronous rotating reference frame in the discrete form and statistical treatment of data accumulated during the period of the fundamental harmonic. The proposed technique allows to evaluate the quality of the line current in a three-phase power system in real time and can be implemented on a microcontroller that does not have a digital signal processing feature. Simulation results and experiments have shown that calculation of the total harmonic distortion of phase current in a three-phase power system by the proposed technique is much faster than by the spectral analysis method.