Optimisation of Reactive Power Control in Electrical Power Systems using Facts Devices

The integration of D-STATCOM into the transmission system enables reactive power compensation in the SEP, with the aim of stabilizing voltage and reducing active power losses. Diverging from conventional models that depend on simplified linear assumptions, this work integrates full non-linear power-flow equations; these are subjected to rigorous operational and security boundaries and are resolved using a Sequential Quadratic Programming (SQP) algorithm. The system architecture is modelled via the Y-bus admittance matrix to capture the complex interactions between generators, load demands, and compensating elements. Within this topology, the D-STATCOM is conceptualized as a controllable shunt element capable of dynamic transitions between inductive and capacitive modes, responsive to immediate grid requirements. Optimal siting is determined through the application of the Voltage Sensitivity Load-Based Index (VSLBI), a metric specifically calibrated to pinpoint network nodes exhibiting high susceptibility to voltage fluctuations. Validation of the methodology's scalability and computational efficiency is conducted across four standard IEEE benchmark systems: the 30-, 57-, 118-, and 300-bus networks. The IEEE case studies validated the stability of the proposed optimization model; the values obtained after integrating the D-STATCOMs demonstrate that the voltage remains within the operating ranges, thereby reducing active power losses. In the sensitivity tests, when the load was increased by 10%, 20%, and 30%, the power system remained stable and did not experience voltage sags. These results validate the D-STATCOM’s ability to compensate for reactive power and dynamically regulate voltage.