What is the primary function of a grid-forming inverter in a tidal energy plant connecting to a weak grid?

The primary function of a grid-forming inverter in a tidal energy plant connecting to a weak grid is to independently establish and maintain a stable voltage and frequency at the point of connection, enabling the tidal plant to operate reliably and contribute to grid stability even when the grid itself has limited capacity or is prone to voltage and frequency fluctuations. A grid-forming inverter actively creates the AC voltage waveform rather than simply synchronizing with an existing grid voltage. This is crucial in weak grids, which are characterized by low short-circuit ratios (meaning they are easily influenced by changes in power flow) and limited ability to absorb disturbances. Traditional grid-following inverters rely on a strong, stable grid voltage to synchronize their output and inject power. However, in a weak grid, the voltage and frequency can fluctuate significantly, causing grid-following inverters to become unstable or disconnect. A grid-forming inverter, on the other hand, acts as a voltage source, actively controlling the voltage and frequency at the connection point. This provides a stable reference for other grid-following inverters and helps to dampen voltage and frequency fluctuations. By establishing a stable voltage and frequency, the grid-forming inverter allows the tidal energy plant to operate reliably, even when the grid is weak or experiencing disturbances. It also provides ancillary services, such as voltage support and frequency regulation, which help to improve the overall stability of the grid. For example, if the grid voltage drops due to a fault or sudden increase in load, the grid-forming inverter can increase its output voltage to support the grid voltage and prevent a blackout. Therefore, grid-forming inverters are essential for integrating tidal energy plants into weak grids, enabling them to contribute to a more reliable and sustainable electricity supply.