Upgrading the Power Capacity of a Three-Conductor MVAC Line by Converting to DC

Abstract

Several countries around the world are undergoing a radical transformation of their electricity networks, with the widespread integration of distributed generation based on renewable energy sources at the center of the change. Under these scenarios, DC links are becoming an attractive option for the infrastructure of modern networks, especially at medium voltage levels. This work is devoted to the integration of DC systems in existing AC networks by converting AC power lines to DC. The work presents a novel method for converting a three-conductor medium voltage AC transmission line to DC. The efficiency of the proposed conversion is assessed in terms of increased power capacity. It is shown that the proposed approach allows for increasing the power capacity of the line by at least 10%. The feasibility and effectiveness of the proposed method are then confirmed by laboratory experiments.

Recent Trends in Power Systems Modeling and Analysis

“…However, the threecable configuration, typical of AC and inherited by some DC systems, does not allow one to exploit the loadability of the cable serving as a return path. In [14], a three-phase MVAC system is converted to MVDC by maintaining the existing cables yet proposing a switching scheme to increase the power capacity of the connection by 10%. The cable connected to the positive pole carries the total current, while at the negative pole, the current is split between the other cables.…”