Low Voltage Ride Through (LVRT) Testing Solution for the Photovoltaic and Wind Power Industries
For variable-speed constant-frequency doubly-fed wind turbines, in the event of a drop in grid voltage, the associated power electronic converters, which belong to the AC/DC/AC type, can generate peak currents on their rotor side, potentially damaging the converter equipment and causing the wind turbine generator to disconnect from the grid. In the past, when wind turbine capacities were relatively small, the protection of the rotor-side excitation device led to disconnection from the grid. However, with the increasing capacity of wind turbines, disconnection from the grid could affect the overall stability of the power grid and even lead to cascading failures. Consequently, foreign experts proposed the issue of low voltage ride through for wind power generation.
The LVRT function varies from country to country and is subject to different national standards. In China, for provincial or regional power grids where wind power capacity exceeds 5% of the total installed capacity, wind farms within the grid area must have the LVRT function.
1.The wind turbines in the wind farm are capable of operating continuously for 625ms without disconnecting when the grid voltage drops to 20% of the rated voltage at the point of grid connection.
2.In case of a grid voltage drop, if the voltage at the point of grid connection recovers to 90% of the rated voltage within 2 seconds, the wind turbines in the wind farm ensure continuous operation without disconnection.
