Coordinated control of step voltage regulator and D-STATCOM in the presence of distributed photovoltaic systems

Volt/VAR optimization (VVO) will keep playing an important role in future as smart distribution grid is envisioned to integrate a large amount of distributed energy resources (DERs) particularly photovoltaic (PV) systems. Current local controls such as line drop compensation (LDC) of step voltage regulators (SVRs) will not be enough once the penetration level of DERs exceeds the hosting capacity of the grid. This situation demands the current volt/VAR control (VVC) schemes to integrate further control equipment and adopt different control schemes. This paper proposes a centralized coordinated control that reduces the distribution losses and tap movements in the presence of distributed PV systems. The control is achieved using SVRs and distribution static synchronous compensator (D-STATCOM) through smart distribution management system (DMS). Simulation studies are performed by using modified quasi-dynamic time-series GE LV Test Network. DigSILENT PowerFactory is used for power system analysis while particle swarm optimization (PSO) is implemented in MATLAB. A comparison with local controllers of D-STATCOM demonstrates the effectiveness of the proposed strategy. The results indicate that there is considerable decrease in the losses and tap movements.