Do grid-forming inverters have overcurrent characteristics?

Abstract: Grid-forming (GFM) inverters are increasingly recognized as a solution to facilitate massive grid integration of inverter-based resources and enable 100% power-electronics-based power systems. However, the overcurrent characteristics of GFM inverters exhibit major differences from those of conventional synchronous machines.

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.

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 do grid-tied PV inverters work?

When a fault (such as a short circuit, flickering, or loss of grid power) occurs on the grid, even if it is transient in nature, the conventional grid-tied PV inverters automatically cut themselves off from the grid. The inverters are configured in this fashion to prevent damage from transients of over current or over voltage.

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.

Are control strategies for photovoltaic (PV) Grid-Connected inverters accurate?

However, these methods may require accurate modelling and may have higher implementation complexity. Emerging and future trends in control strategies for photovoltaic (PV) grid-connected inverters are driven by the need for increased efficiency, grid integration, flexibility, and sustainability.