Inverter real power

Based on real-time measurement of the grid impedance, the unintended reactive power is estimated and autonomously compensated in the inverter. The method removes the fluctuating reactive power component, while still permitting unrestricted manual control of the reactive power.

Power generation flowing through the transmission line causes unintended flow of reactive power to the grid side, as the transmission reactance consumes reactive power. Thus, the grid-side reactive power becomes coupled with the active power production of the photovoltaic inverter, which fluctuates along with irradiance conditions.

For an inverter to handle reactive power it must have the ability to run backward and absorb the reactive energy. This technology is called . The inverter can provide reactive power based on a function of the entire size of the inverter, not just on the level of generation.

An inverter often has a transformer as part of the circuit that attaches to an AC input and so is often an inductive load from the view of the power company. sources, such as solar power, provide not only electricity but can also be used to generate reactive power.

The flow of reactive power in the transmission line increases the total current and Joule losses in the line. In addition, a large proportion of unintended reactive power may destabilize the inverter in very weak grids. Consequently, the unintended reactive power imposes limitations to maximum active power feed from the PV inverter.

Manual reactive power control during autonomous operation Most of the new PV inverters are capable of reactive power support. The proposed autonomous compensation method defaults the grid-side reactive power to zero, but does not interfere with external reactive power control.