The use of harmonic phasors and complex impedances in renewable power plant assessment

Harmonic assessments are required by renewable power plants to show the plants comply with limits set by network operators. To identify sources of harmonic emissions, matching recorded harmonic magnitudes of voltage and current to an impedance magnitude is effective when the load impedance is substantially higher than the grid impedance. During operation, low impedance characterizes renewable power plants. To correlate harmonic voltage and current measurements to installation and grid impedance is impossible under these circumstances. This paper shows that by correlating the phase angle of phasor recordings to a complex impedance angle is an effective method of identifying the source of harmonic emissions. The calculation of prevailing phasors simplifies the graphical interpretation of recorded data on polar plots.