DYNAMIC VOLTAGE SECURITY ASSESSMENT USING A FUZZY SEVERITY INDEX

This paper describes a new approach, based on fuzzy-set theory, to dyn amic voltage security assessment. The development enables the large-sc ale nonlinear voltage instability assessment problem to be reduced to a fuzzy severity index, by which the dynamic voltage secure/insecure s tate is conservatively assessed. Besides providing a mere two-region d emarcation, the magnitude of the severity index can generally give a r elative severity indication to discriminate between various insecure p ost-disturbance system states. Preliminary results show that the appro ach presented here is promising for on-line use because of its relativ ely light computational burden.