Grid Influences from Reactive Power Flow of Photovoltaic Inverters with a Power Factor Specification of One

This paper discusses the influence of unintended reactive power flow caused by photovoltaic (PV) inverter systems with a power factor specification of one on the grid voltage and grid loss. In theory, the apparent power feed-in of these PV systems should be equal to the active power feed-in. Observations in distribution grids have shown a reactive power flow caused by these systems. The main purpose is, if this influence has to be considered in grid planning and power system management in smart grids. Therefore, measurement data of several low voltage grids is used. Three different scenarios for the unintended reactive power are simulated. Under normal operating conditions, the unintended reactive power is not relevant. Nevertheless, if voltage or overload problems are not explainable, they can be a result of the unintended reactive power flow. This approach is very helpful for network operators to locate and understand the reasons for grid problems.