Modeling and Performance Analysis of Continuously Variable Series Reactors (CVSR) for Congestion Management in Meshed Distribution Networks

Distribution systems, particularly in densely loaded urban areas, frequently experience transformer overloading during peak consumption hours. Rather than resorting to costly infrastructure reinforcement or complex Flexible AC Transmission Systems (FACTS), this paper proposes a cost-effective optimization and control approach utilizing a Continuously Variable Series Reactor (CVSR). Unlike FACTS devices that rely on expensive power electronics, the CVSR capitalizes on magnetic core saturation to regulate reactance, offering a robust solution at a fraction of the cost (~$10/kVAr). The CVSR regulates the reactance on the primary side of the transformer via magnetic core saturation to control power distribution among transformers. In this study, the steady-state framework of the CVSR is derived and integrated into power flow formulations. The proposed model is validated using a two-parallel transformer system and tested on the heavily meshed IEEE 342-Node Low Voltage Networked Test System (LVNTS). Simulation results demonstrate the CVSR effectively relieves transformer overloading by redistributing power flow, thereby enhancing system flexibility and allowing utilities to avoid or defer extensive grid upgrades.