Measurement and assessment of power quality characteristics for photovoltaic systems: Harmonics, flicker, unbalance, and slow voltage variations

This paper provides guidelines for the measurement and assessment of power quality (PQ) characteristics for photovoltaic (PV) systems at a site. These include harmonics, flicker, unbalance, and slow voltage variations. A description is given of the PQ indices and objectives. Such indices and objectives help distribution network operators (DNOs) to report on PQ performance to third parties when collecting and presenting PQ data. The indices are obtained with the measurement procedure described in this paper. Previous work explained how to specify the objectives, which were initially based on the planning level proposed in IEC technical reports. The field measurements taken in a currently operating MV PV power plant were characterized in terms of PQ indices and compared to the objectives for this PV power plant. Results showed that within the context of the current state of PV technology, the disturbance objectives for the PV power plant monitored were not always met. (C) 2012 Elsevier B.V. All rights reserved.