Reactive power control of photovoltaic systems based on the voltage sensitivity analysis

This paper addresses the voltage fluctuations caused by the output variability of photovoltaic (PV) systems. Due to the significant line resistances inside a distribution network, variations in the active power produced by a PV system can lead to fluctuations in bus voltages and result in the excessive tap-change operations of voltage regulation devices. Based on the voltage sensitivity analysis, the paper presents a reactive power control method for PV systems to mitigate the voltage fluctuations. The method is local and obviates the need for remote measurements. Also, the method considers the loss associated with the reactive power production. The performance of the method is illustrated on the IEEE-123 bus distribution network. Measurements from two actual PV systems are taken into account and the wavelet based fluctuation power index is used to evaluate the method performance. Simulations (in OpenDSS) are presented to assess the voltage regulation characteristics under different load conditions.