Reactive Power Control Modes in Smart Inverters for Overvoltage Mitigation: Impacts on LVRT Performance — A Case Study in Gorontalo, Indonesia

The increasing penetration of photovoltaic (PV) power generation into distribution networks presents an overvoltage challenge during normal operations. Smart inverter reactive power control modes are promising solutions to address this challenge. To mitigate overvoltage, reactive power control modes are commonly configured with conservative limits to protect equipment. However, during severe faults, a higher reactive current availability is required to comply with low-voltage ride-through (LVRT) requirements. Therefore, reactive power control modes should be capable of operating under both normal and fault conditions. This study investigated how the standard reactive power control modes used for overvoltage mitigation affected the LVRT performance. A case study was conducted on a 2 MWp PV plant connected to a real medium-voltage feeder in Gorontalo, Indonesia, which experienced overvoltage during peak PV injection. To assess this impact, a multifunctional control framework was developed that integrated a reactive power controller (Fixed VAr, Fixed power factor, Watt–VAr, and Volt–VAr), fault detection logic, an LVRT mechanism, and a current limiting scheme. Three-phase symmetrical faults were simulated with variations in the reactive power limits, voltage sag depths, and delayed fault clearing. The results showed a clear trade-off: tighter reactive power limits reduced steady-state overvoltage but degraded LVRT performance by lowering reactive current injection and delaying voltage recovery. Moreover, each control mode exhibited distinct dynamic responses, implying different parameter-setting priorities. These findings underscore the need to configure reactive power limits and firmware parameters to sustain overvoltage mitigation during normal operation, while preserving LVRT during faults.