Alleviating congestion of hybrid urban grid by VSC-control and AC-line switching

As electricity load in large cities overgrows these years, mainly due to the increasing penetration of electric vehicles, the urban transmission networks are subject to the high risk of congestion because of insufficient planning. Reconfigure the high-voltage distribution network (HVDN) is an efficient way to mitigate the urban congestion. However, the discrete load transfer amount is not precise that might cause load curtailment, and the computation burden is also heavy when the system scale is enormous. In recent years, the emergence of voltage source converter (VSC) as the core components of DC transmission technique provides a new control measurement featuring fast and flexible. Nevertheless, its adjusting capacity is limited and subject to the system topological structure. Thus this paper proposed a coordinative control model that combines the load transfer capability of the HVDN and flexible and precise control of VSC to alleviate the urban transmission congestion. Numerical results showed that the congestion lines could be efficiently relieved thus defer further investment in the transmission network.