Investigation of oscillations caused by voltage control from smart PV on a secondary system

This paper presents the results of an investigation of undesirable impacts of voltage control actions from autonomously acting residential smart Photovoltaic generators (PVs) in response to overvoltage conditions. The investigation was performed with Quasi-Static Time Series (QSTS) simulations for a real-world secondary distribution system. We conclude that Volt-Var control curve settings for smart inverters should be selected carefully to avoid severe power quality and stability issues. Very conservative settings are curves with slowly rising slopes and low max/min values, but these curves curb the voltage control capability of smart inverters significantly. The addition of a Var Ramp Rate Limit eliminates oscillations, but the voltage control response is significantly slower. In future work, we will extend the study to the primary system to investigate larger PV penetration levels and the interaction of smart PV with traditional voltage control equipment.