A method for finding a pair of multiple load flow solutions in bulk power systems

The authors discovered that the convergent characteristic of load flow calculation by the Newton-Raphson method in rectangular coordinates has a unique linearity. It tends to converge straight toward two multiple solutions when they are located close to each other. On the basis of this feature, the authors propose a method for solving two close solutions in bulk power systems. The results of applying this method to a heavily loaded practical 233-bus system and the Klos-Kerner 11-bus system verify its robustness and ability to find solutions successfully and quickly. The proposed method is so fast that it can be applied to an online voltage security system.<>