Using Solar PV Inverters at Night for Voltage Stabilization: a Case Study

Installation of grid-connected rooftop solar power generation modules has been allowed in Sri Lanka since 2008. The paper analyzes the potential use of solar power inverters at night to feed reactive power to the low voltage (LV) network. The LV network typically has undervoltage issues at the evening peak-time, and the PV inverters distributed along the line can be used to eliminate or reduce such undervoltage issues. The paper proposes an algorithm to determine the suitable operating power factor of each inverter connected to the feeder. A case study of a LV distributor with solar PV inverters is presented, to demonstrate the application of the algorithm. Financial benefits to customer by introducing a reactive power tariff is assessed. The paper concludes that such a system would yield net benefits to the utility.