Voltage stability assessment: An approach with expanded Newton Raphson -Sydel

Voltage instability is major cause of cascading failures in the current power systems. Static assessment of voltage stability has been used widely to draw the secure margin of voltage security for the system components. Among the many methods reported, Conventional Newton Raphson method is popular but it suffers from curse of singularity on its Jacobian matrix which precludes converging onto the solution. To overcome this problem, Continuation Power Flow (CPF) method was come up. CPF method is a very powerful method that can give the solution without having the singularity problem. The CPF method has then been improved using new CPF-GMRES method. In contrary, NRS (Newton - Raphson - Seydel) is old method but is fast and accurate. This paper expands existing NRS method which then demonstrated that it is more reliable and faster than CPF-GMRES and NRS. The algorithm tested on practical 350 bus network in IRAN (Khorasan region).