Phasor-based assessment for harmonic sources in distribution networks

• Proposing phasor-based harmonic assessment approach for distribution network.
• Using new index that incorporate phase angle information into harmonic calculations.
• Conducting the system-wide harmonic studies in comparison with local harmonic analysis in distribution networks.
• Analyzing impact of phase couplings and phase balancing on harmonic propagation through overhead lines.

Phasor-based interdependencies of multiple harmonic sources, especially Distributed Energy Resources, on distribution networks are analyzed in this paper. A new index, Phasor Harmonic Index (IPH), is proposed by the authors. IPH considers both harmonic source magnitude and phase angle for different harmonic orders. Other commonly used harmonic indices are based solely on magnitude of waveforms. A very detailed model of a distribution network is used in the harmonic assessment. With the help of the detailed distribution network model, the phase couplings and the phase balancing impacts on harmonic propagation between three phases are investigated. Moreover, effects of harmonic source phase angle deviations are analyzed at both the customer side and the substation side. This paper investigates the importance of phase angles in harmonic assessment and how distribution network characteristics can be analyzed appropriately with phasor-based harmonic studies. In addition to device level harmonics, system level harmonic propagation need to be considered.