Design and Realization of a Static-Commutated Device for Low Voltage Regulation

The widespread expansion of distributed generation (DG) has brought economic and environmental benefits, but it has also posed technical challenges for low voltage (LV) distribution networks, related to unpredictable behavior of DG. In particular, ensuring adequate voltage amplitude is critical, especially for active users that include both generation and load. DG devices can withstand short-term voltage fluctuations without degrading network service quality; however, long-term voltage variations can negatively impact grid operations, causing voltage increases, changes in on-load tap changer (OLTC) regulation profile, power flow reversal, and even tripping of DG. This research focuses on LV regulation devices designed to compensate for long-term voltage variations in the presence of DG. It expands the ‘proof of concep’ for a simple, compact, and low-cost low-voltage control device, based on a two-winding transformer that can change its configuration through static commutation. The paper offers a more in-depth exploration of various aspects of the proposed device's design, by proposing and implementing a novel transformer design, introducing a new control structure based on a fast-forced commutation, and considering an upgraded electronic design that incorporates device protection and remote control capabilities. The document comprises multiple laboratory tests carried out on the device across various operating scenarios. These tests show the tangible improvements achieved through the implementation of the new architecture and highlight some of the latest advancements made in the prototype.