Enhanced Power Injection Strategies for Voltage Sag Minimization: Integrating the Maximum Apparent Power of the Converter and the Thévenin Equivalent

Due to the increasing penetration of distributed energy resources, Brazilian grid codes have been modified, specifying how the interaction between these devices and the grid should be executed. Furthermore, modifications to grid codes enable the expansion of ancillary services, such as assisting in voltage regulation and minimizing voltage sags. In this context, this article proposes a comparative study of three power injection methods during voltage sags that complement an adaptive control based on Thévenin impedance and voltage, which uses equivalent information and maximum apparent power to expand power injection. These variables are employed to determine the amount of injected power, opening up the possibility of expanding injection up to the maximum apparent power, if necessary, while also avoiding violations of low voltage ride-through requirements. By comparing the methods, it is shown in this article which one is the most robust in terms of minimizing voltage.