Characterization of harmonics in a utility feeder with PV distributed generation

Abstract

A thorough analysis of the harmonic characteristics of a feeder in the London Hydro distribution system is presented in this paper. This feeder interconnects several solar photovoltaic (PV) arrays as well as two shunt capacitor banks. Harmonic measurements were acquired over one week at critical locations in the feeder. The analysis highlights higher than expected harmonic distortion levels, though still within limits established in IEEE 519-1992. Harmonics injected by the solar systems are partially additive, contributing approximately 0.1% to the total harmonic distortion (THD) at the feeder terminal. Significant 3rd, 5th, 7th, 9th, 11th, and 13th harmonic levels are discovered. Although the system is not subject to an immediate risk, future addition of inverter-based distributed generation (DG) coupled with possible resonant conditions presents the prospect of a rise in harmonic distortion levels beyond acceptable limits.