Assessing harmonic penetration in terms of phase and sequence component indices

The purpose of this paper is to simulate a balanced and unbalanced network with the DIgSILENT PowerFactory software package and to perform a harmonic penetration study on these networks in terms of phase and sequence component indices and verify the results obtained by hand calculations. The hand calculations were done using the IEEE Working Group Definitions for calculating powers in a system with nonsinusoidal waveforms. Modelling and the correct referencing of harmonic source phase angles are important when calculating power indices. A third case study is conducted to demonstrate two methods of phase angle referencing and modelling of harmonic sources, one used by DIgSILENT and the other used by the ERACS software program. The spectrum of a drive measured in the field is used. The results are compared and they show that the same values for the power indices are obtained provided that the harmonic phase angles are adjusted correctly.