Quantification Method for Maximum Access Capacity of Renewable Energy in Multi-infeed System with Temporary Overvoltage Constraints

After a fault disturbance, there is a risk of temporary overvoltage in areas where renewable energy is aggregated, which can lead to the disconnection of renewable energy and threaten the safe and stable operation of the power grid. The capacity of input access to a multi-input system affects the temporary overvoltage level. Therefore, there exists a maximum access capacity that prevents the renewable energy from disconnecting from the grid in the event of a fault disturbance. To solve for the maximum access capacity, this paper first analyzes the reasons for the temporary overvoltage in the renewable energy AC transmission system caused by the fault disturbance, according to the renewable energy low voltage ride through (LVRT) control strategy. Then, a mathematical model for solving the temporary overvoltage maximum value in such a system with multiple inputs is presented. On top of that, an optimization model for the maximum access capacity of renewable energy, which is subject to the constraint of overvoltage safety, is established. The optimization model is solved using the tracking center trajectory interior point method to obtain the maximum access capacity of the multiple-input system and the optimal output distribution of each renewable energy source. Further, the cosine similarity is used to evaluate which output distribution is better for the same access capacity. Finally, the effectiveness of the proposed method for quantifying the maximum access capacity of multi-feeder systems is verified in a practical engineering example.