Assessment of Decentralized Reactive Power Control Strategies for Low Voltage PV Inverters

The increase of solar PV installations at the distribution grid level causes new challenges that Distribution System Operators have to resolve. Amongst those challenges, one is the voltage fluctuation at the distribution grid level due to intermittent active power injection from solar PV systems. A well-known solution to regulate the voltage is the local consumption or production of reactive power, that is extensively used at the transmission grid level by generators or Flexible AC Transmission Systems. This paper discusses the impacts of low-voltage control by reactive power injection from commercialized rooftop PV solar inverters. Using a fully decentralized approach, several state of the art strategies for PV inverters’ power factor control are compared, showing that some of these decentralized strategies are a viable solution to control voltage in distribution grids. The methodology used for the assessment of these control strategies includes the impact on the inverters’ life time (measured as the annual cost for each strategy) as well as the impact on the voltage profiles of a real grid representing an Indian community with more than 200 households.