Implementing Volt-Var Control in Meshed Low Voltage Grids

Hyper-dense urban areas often employ meshed power grids to increase redundancy, resiliency and contingency tolerance. Transformer load balancing and voltage profile management are key concerns for such networks. Furthermore, the impedance of the network is much lower than traditional radial distribution systems making the fault current levels extremely high. Traditional FACTS based Volt-VAr approaches fail owing to the fault current levels as well as the space and environmental constraints for this application. This paper proposes a new concept called Stacked Isolated Voltage Optimization Modules (SIVOM), which utilizes coaxial winding transformers to achieve power flow control as well as Volt-Var control. The efficacy of the approach has been demonstrated through simulations on a synthetic low voltage meshed grid. Experimental verification on a laboratory prototype is also presented in this paper. The fail-normal approach taken here ensures that the system's operation is not affected by faults in the modules.