Stability Analysis and Setting Guideline for Inverter-Based Distributed Energy Resources with Volt-Var and Volt-Watt Control Functions

Smart inverter grid support functions such as volt-var and volt-watt have been proven effective in alleviating overvoltage and voltage variation issues caused by high penetration of distributed energy resources (DERs) on the distribution network. However, because of the dynamic nature of volt-var and volt-watt control functions, they may cause unstable voltage oscillation, especially with aggressive control settings. Based on small signal stability analysis, this paper proposes an easy-to-implement approach to identify the setting range for volt-var and volt-watt control functions that ensures stability. This setting guideline is applicable whether volt-var and volt-watt controls are utilized individually or simultaneously. Application of the method to one and multiple inverter-based DERs is then demonstrated and verified against dynamic simulation results on a National Grid distribution feeder.