A photovoltaic system includes solar cells and photovoltaic inverters configured to convert direct current generated by the solar cells to alternating current. Grid voltage at the point of interconnection (POI) of the photovoltaic system and the power grid is measured and compared to a setpoint. A control signal is generated based on the measured grid voltage. The control signal is provided to the photovoltaic inverters. The control signal is adjusted to cause the photovoltaic inverters to generate or absorb reactive power to respond to transient grid voltage changes.