Instantaneous Active/Reactive Power Control Strategy for Flicker Mitigation Under High PV Penetration

摘要

In recent years, renewable energy sources, especially Photo- Voltaics (PVs), are being integrated into the Low-Voltage (LV) grid in massive numbers. Inherently, intermittent nature of PVs may cause power quality issues like the voltage rise and the flicker. Firstly, this paper investigates the Finnish LV grids of geographically dispersed areas, for the voltage flicker problem due to solar irradiance fluctuations. Secondly, instantaneous-active/reactive power-control methodology for PV is proposed for flicker problem mitigation. It makes use of the short-circuit impedance value of the feeder from the transformer till the point of PV connection and active power fluctuations, for reactive-power compensation calculation. However, during the peak generation period, the PVs are to be momentarily curtailed to reduce the voltage fluctuation, hence flicker. To support the proposed strategy, simulations are conducted on MATLAB, on various grids differing in topologies. The results reveal the correlation between voltage flicker and solar irradiance fluctuation and it was observed that the employment of the devised control strategy significantly improved the long-term flicker index at the weakest grid node.