ATC determination for the AC/DC transmission systems using modified CPF method

With the expansion of the power systems, DC power transmission has been increasingly applied in interconnection of grids. The determination of Available Transfer Capability (ATC) for the AC/DC transmission systems is significant to the system planning and operation. So far, most studies have been focused on ATC determination for AC transmission systems, few are on the AC/DC system ATC determination. In this paper, the ATC determination model for the AC/DC systems is proposed. Multi-terminal DC (MTDC) system is considered in ATC computation model. Conventionally, the power injection variations are determined by load variations and generation dispatch, both of them are nonlinear. To model these nonlinear variations, an alternate iterative continuation power flow (CPF) method with multiple load variations and generation economic dispatch patterns is presented to solve the proposed model. The MTDC system configurations, the converter control strategies and the transformer´s tap adjustment strategies are incorporated to this modified CPF algorithm. The modified IEEE 30-bus test system is used to verify the presented approach.