Evaluation of Power Grid Vulnerable Region Based on Sensitivity Technique

By use of sensitivity technique the authors give the definition of the index of power grid vulnerable region and propose an algorithm to calculate parameter sensitivity.By means of the proposed algorithm the sensitivity of nodal voltage to any network parameter can be obtained,such as line reactance,variation of reactive power of power grid and so on.Considering the sensitivity of virtual nodal voltage to line reactance and variation of reactive power of power grid comprehensively,the voltage instability index is put forward.The influences of the variation of system load and that of line structure on power grid voltage are analyzed,from this the vulnerable region and vulnerable bus of power grid voltage are determined.Applying the proposed algorithm to IEEE 30-bus system and IEEE 118-bus system,the efficiency of the proposed algorithm is validated by the simulation results and its application value is proved.