A new method for directly calculating the sensitivity of loading margin

The loading margin of power system is influenced easily by parameters of the system, that is, the sensitivity of loading margin with respect to any parameters. A new method is derived in this paper to directly calculate the sensitivity of loading margin to voltage collapse. This method only needs to solve linear equations of system with extended Jacobin matrix. Because of avoiding the iteration step to compute the left eigenvector corresponding to zero eigenvalue, this method is much more simpler and quicker for computing sensitivity, and more applicable for analyzing static voltage stability. A single machine power system model is studied and simulation results verify the validity of the method for large power systems.