Mathematical representation of harmonic resonance phenomenon and harmonic compensation in PMSG based wind farms under feedforward compensation of the grid voltages

Abstract

This paper mainly focuses on harmonic resonance analysis and harmonic compensation in electrical power grid including PMSG-based wind turbines. In this way, first, harmonic resonance representation and impedance model of the study system is presented by taking the grid-side converter control into account. Then, it is mainly dealt with the harmonic resonance analysis in the study electrical power grid under feedforward compensation of the grid voltages. In this paper, under feedforward compensation of the grid voltage, impacts of the bandwidths of the voltage/current measurement filters on harmonic resonance response of the system are investigated by using frequency scan and harmonic resonance mode analysis (HRMA) approaches. It is shown that by increasing the voltage measurement filter bandwidth, resonance damping is weakened and the magnitudes of driving point impedances increase. Hence, feedforward compensation of the grid voltage in a limited frequency range results in better resonance damping in comparison with feedforward compensation in a wide frequency range. On the other hand, by increasing the current measurement filter bandwidth, the new resonant modes are not added to the network. It is also shown that employing passive filters significantly reduces the driving point impedances of all buses at the different harmonic orders.