A new Supervisory Strategy of a modified D-STATCOM with Dual DC Source in Smart Distribution Grids

This study presents a novel approach in applying a fuzzy logic controller-based decision making for power management of the modified D-STATCOM converter supplied by a dual DC source (battery and supercapacitor) to achieve a robust and superior performance for voltage regulation. Conventional D-STATCOM is a compensator-based power electronic device, employed as a reactive power source in AC power systems to maintain voltage stability. However, these devices have a limited ability to mitigate voltage fluctuations caused by active power disturbances. To fully exploit the potential of the D-STATCOM device, energy storage technology has been combined with D-STATCOM to support the grid with reactive and active power in the microgrid. The proposed approach employs the advantage of high-power storage unit (supercapacitor) and high energy storage unit (battery) with a D-STATCOM configuration to avoid the limitations of using only one specific storage unit. Furthermore, the fuzzy logic management approach distributes the power required almost instantaneously between the energy sources. Thus, it is possible to implement an intelligent real-time energy management controller able to effectively distribute the required current from the HESS and provide good performance of the voltage at the PCC. Verification of the control designs has been achieved through simulation using MATLAB/SIMULINK based on the derived analytical model in state-space form. Comprehensive simulation results show that the modified D-STATCOM topology-based HESS with a proposed fuzzy controller demonstrates significant improvements over conventional D-STATCOM controllers in supporting voltage stability under different conditions in distribution networks.