Abstract
Two-terminal High Voltage Direct Current HVDC transmission links are in operation throughout the world. They are key elements in electrical power networks, their representation is oversimplified or ignored in most power system studies. It is therefore necessary to adequately model the HVDC transmission links and integrate them in the load flow analysis of the complete AC/DC system. In this paper, the well known Newton-Raphson method for the load flow analysis is modified to achieve compatibility for AC/DC systems with integrated DC links in the AC network. The modified Jacobian equation includes the DC real and reactive power at the AC/DC buses, and their dependency on the AC system variables. The modified Newton-Raphson method is evaluated on an AC/DC test system with a load flow computation in Power World Simulator PWS and the results are presented.