A stability vulnerability in the interaction between Volt-VAR and Volt-Watt response functions for smart inverters

摘要

The strong uptake of PV systems, both within Australia and internationally, and particularly for small-scale systems within residential distribution networks, has raised concerns over potential impacts such as over-voltages. Responding to these potential issues, distribution network operators are beginning to impose restrictions on PV installations, including limiting system size, ramp rates, and exporting and managing reactive power. Additionally, inverter standards (such as AS/NZS 4777) are being updated with revised power quality functionality such as Volt-VAR and Volt-Watt control functions. This paper considers a specific case of the interaction between Volt-VAR and Volt-Watt inverter functions and demonstrates, both analytically and via a simulation example, that this interaction can lead to voltage instability if not adequately designed.