A Simple and Efficient AC-DC Load-Flow Method for Multiterminal DC Systems

A new ac-dc Load-flow method for multiterminal dc-ac systems that uses a novel approach to solve the equations of the multiterminal dc system is described. A simplified version of the ac-dc load-flow method with all of the capabilities of estabLished Newton´s methods is shown to have the best qualities of simultaneous and sequential solution ac-dc methods combined. Next, important features such as discrete taps, distinction between scheduled voltage and scheduled angle controls, fixed taps and extended phase controls, and current limits are incorporated to enhance the versatility of the method, especially for transient stability studies. Numerical examples are used to illustrate the various features of the method. Its performance is compared with those of an established Newton´s method and a recent method. The method is simpLe to program, economical and fast.