A Novel Unified Methodology to AC/DC Hybrid Power Flow

Power flow is much more difficult to solve in AC/DC hybrid system with the widespread expansion of DC systems. Firstly, this paper designs a mechanism that transforms parameters in DC system to those in AC system so that the calculation can be done in an integrated framework without changing the relationships between different parameters and variables of DC system. The transformation mechanism is then applied to the converter's external characteristic in the unified framework, considering the nonlinearity of the line commutated converter and pulse width modulation converter. Finally, an algorithm for solving AC/DC hybrid power flow is developed, performing much more efficiently than traditional methods due to the decreased parameters of the converter, especially for large-scale systems. AC/DC hybrid systems with different operation modes are studied to verify the proposed methodology for its performance and feasibility.