###### Abstract
Power quality (PQ) improvement strategies are essential for maintaining the reliability and efficiency of modern power systems, particularly as they become increasingly complex with the integration of renewable energy sources and advanced technologies [11; 12]. One of the primary strategies is the implementation of power conditioning devices, such as dynamic voltage restorers and static synchronous compensators. These devices help to mitigate voltage sags, swells, and interruptions by providing immediate corrective action to maintain voltage stability and continuity of supply. Another crucial strategy involves the use of advanced harmonic filtering techniques. Harmonics, generated by non-linear loads and power electronic devices, can distort the electrical waveform, leading to equipment overheating, increased losses, and interference with communication systems. Active and passive filters are deployed to eliminate or reduce harmonic distortion, improving overall power quality. Active filters dynamically adjust their response to changing harmonic levels, while passive filters provide a steady reduction in specific harmonic frequencies [10; 13]. PQ issues in electrical distribution systems can be effectively addressed using Distribution Static Synchronous Compensators (DSTATCOMs). Among the various strategies for PQ improvement, DSTATCOMs have emerged as highly effective solutions. The integration of DSTATCOMs into power systems involves multiple topologies, each designed to cater to specific system requirements and configurations. One widely used topology is the three-phase three-wire (3P3W) DSTATCOM, implemented in 3P3W distribution systems to improve PQ and compensate loads. This topology is subdivided into non-isolated and isolated voltage source inverter (VSI)-based configurations. Regarding non-isolated 3P3W VSI-based DSTATCOMs, they can be further categorized into topologies using three-leg or two-leg VSIs. The three-leg VSI topology is commonly discussed in the literature for its effectiveness, whereas the two-leg VSI topology is preferred for its reduced number of switching devices, though it faces challenges in regulating DC capacitor voltages and requiring high DC voltages [14; 15]. However, isolated 3P3W VSI-based DSTATCOMs involve using three single-phase VSIs or configurations with a \(Y/\Delta\) transformer, which offers system isolation and matches the kVA rating required for reactive power injection. Despite the higher number of switching devices in some isolated topologies, they provide benefits such as isolation and flexibility in transformer configurations to meet specific PQ improvement needs. Another crucial topology is the three-phase four-wire (3P4W)DSTATCOM, employed in 3P4W distribution systems. These topologies are designed to handle the additional neutral current and provide effective compensation for nonlinear and unbalanced loads in such systems. By implementing various configurations of 3P4W DSTATCOMs, including those with split capacitors and multiple VSIs, PQ issues like harmonics, voltage sags, and swells can be mitigated efficiently [15]. The control strategies for DSTATCOMs can enhance the overall system performance by providing reactive power support and maintaining power quality. They aim to enhance overall system performance and encompass several advanced methodologies. The synchronous reference frame (SRF) theory is a key approach in power electronics and power systems. It uses the supply voltage to derive a rotating reference frame synchronized with the grid voltage. This synchronization is achieved by employing the grid voltage components, typically represented by sine and cosine values, in the Park transformation that converts the three-phase load current quantities into direct (d-axis) and quadrature (q-axis) components in the SRF. This transformation is crucial as it facilitates the precise regulation of reactive power, maintaining optimal PQ.