The reactive power voltage control strategy of PV systems in low-voltage string lines

摘要

In order to solve the voltage over-limit problem of distributed photovoltaic(PV) connected to string lines, it is feasible to fully utilize the reactive power regulation ability of PV systems to adjust the line's voltage. In this paper, based on analyzing the mechanism of the point of interconnection(POI) of PV systems voltage over-limit and the voltage sensitivity of low-voltage string lines, a reactive power voltage control strategy named Q(U, P) was proposed, which is based on the POI voltage and the active power of PV. This control strategy inherits the advantages of Q(U) and cosφ(P) control strategies, determines the reactive power reference value by detecting the POI voltage and active power output of the PV systems. The simulation results show that the proposed control strategy satisfies the grid voltage within the rated range, the total absorbed amount of reactive power is lower and the active and reactive loss of grid are less than the existing control strategies.