Abstract

Voltage sag is a pervasive issue in power systems, demanding effective solutions. Among the key technologies employed to combat voltage sags, the Dynamic Voltage Restorer (DVR) stands out. Positioned in series between the power source and the load, the DVR plays a vital role in mitigating voltage sags. To maximize its effectiveness, various compensating methods are available, including the pre-sag method, in-phase method, and in-phase advance compensation. One crucial aspect of DVR operation is the synchronization of the injected voltage with the phase of the supply voltage. This synchronization is pivotal for the DVR to accurately and swiftly compensate for voltage sags caused by short-circuit currents. To achieve this synchronization, the work described here employs the Discrete Fourier Transform (DFT) for phase detection, a critical step in DVR operation. Furthermore, the control strategy plays a significant role in the DVR's ability to mitigate voltage sags effectively. In this project, the hysteresis control technique is combined with Proportional-Integral (PI) control, and the results are compared with those obtained from a Proportional-Integral-Derivative (PID) controller. This comparative analysis provides valuable insights into the performance of these control strategies and their effectiveness in enhancing power quality by rectifying voltage sags. The findings of this study contribute to the optimization of DVR systems, offering improved voltage sag mitigation in power distribution networks.

Key words: Voltage Sag Mitigation, Dynamic Voltage Restorer (DVR), Hysteresis Control, Discrete Fourier Transform (DFT)