ANALYSIS ON HARMONIC PROPAGATION THROUGH DISTRIBUTION TRANSFORMERS

Abstract

Harmonics are one of the power quality issues on distribution networks that need to be concerned when the connected solar photovoltaic (PV) sources are increasingly. The paper analyzed cases of harmonics generated from PV propagating between medium and low-voltage distribution grids through distribution transformers. Harmonics from the PV on the low-voltage side propagate to the medium-voltage side of the transformer with a low degree of influence and inversely proportional to the short-circuit power of the system. Meanwhile, harmonics from the medium voltage side will effect the low-voltage grid, especially when the low-voltage side has compensating capacitors and low load capacity. The solution of using dynamic reactive power compensation on low-voltage side can reduce the impact of harmonic propagation from the high-voltage side which improves power quality.