Calculation of TTC for AC/DC Power Systems Based on Improved Continuation Power Flow

A model of total transfer capability (TTC) for the AC/DC system with multi-terminal voltage source converter DC (VSC-MTDC) system is set up in this paper. As the load and generator power in traditional continuation power flow (CPF) algorithm increased with equal proportion, a novel continuous power flow approach based on economic operation of power grid is proposed. In the method, taking the minimum generation cost as the goal, the distribution of generator output is optimized by economic dispatching based on linear programming method, which can avoid the defects of some existing methods that caused by the piecewise linearization of incremental ratio of generator consumption curve. The distribution of load increment and the parameters of VSC control modes are optimized by mathematical optimization method to minimize the network loss, which can get the TTC under economic conditions. Finally, cases study based on modified IEEE 9-node system and modified IEEE 30-node system verify the rationality and effectiveness of the proposed methods. (paper)