Targeted conversion of AC lines to DC lines for improved power system dispatch

In this paper the concept of targeted conversion of AC lines to DC lines is proposed for improved security-constrained economic dispatch by incorporating the converted line into the formulation to improve flow pattern control and relieve flow constraints on both the converted line and the remaining AC system. The proposed model treats the flow on the converted line as an independent control variable for the operator to utilize. It is shown that the introduction of this additional control variable significantly decreases the dispatch cost through congestion relief. Wind curtailment due to transmission congestion, is also shown to be significantly relieved. The technical feasibility of the implementation, combined with the economic benefits, suggests that targeted conversion of AC lines to DC lines a promising approach to best utilizing transmission grid for maximized social welfare. Illustrative examples on a 24-bus system demonstrate the technical feasibility and economic benefits for renewable energy resources by use of the proposed conversion.