Photovoltaic inverter overload operation capability

Why do PV inverters have over loading capability?

Consequently, the PV inverters with the over loading capability achieve better voltage support showing the reduced voltage dip with the magnitudes of Δ V2, Δ V3 and Δ V4, for 150, 200 and 280% overloading capability, respectively. Applying the overloading capability of the inverter can speed up the voltage recovery after the fault condition.

How to provide voltage support in PV inverter?

To provide voltage support at the PCC, reactive power is injected into the grid under fault conditions as per the specified grid codes. As previously discussed, the simultaneous injection of peak active power from PVs and reactive power into the grid for voltage support can trigger the over current protection mechanism in PV inverter.

What is over current protection mechanism in PV inverter?

As previously discussed, the simultaneous injection of peak active power from PVs and reactive power into the grid for voltage support can trigger the over current protection mechanism in PV inverter. The triggering of over current protection will lead to disconnection of inverter from the grid which is unfavourable during LVRT period.

How is inverter capacity exploited?

In this case, the inverter capacity is exploited by partially injecting both active and reactive power under fault conditions. Since the generated active power is not high, the remaining inverter capacity is utilized by injecting reactive power as in (30).

What are the goals of grid-connected PV inverters?

Under grid voltage sags, over current protection and exploiting the maximum capacity of the inverter are the two main goals of grid-connected PV inverters. To facilitate low-voltage ride-through (LVRT), it is imperative to ensure that inverter currents are sinusoidal and remain within permissible limits throughout the inverter operation.

How to ensure maximum exploitation of the inverter capacity?

To provide overcurrent limitation as well as to ensure maximum exploitation of the inverter capacity the performance of the proposed control strategy, is evaluated as per the three generation scenarios given below: In this case, the inverter’s capacity is majorly exploited through the injection of active power under normal operating condition.