Implementation of ROSE for on-line voltage stability analysis at ISO New England

This paper describes the implementation of Region Of Stability Existence (ROSE) software at ISO-NE for on-line estimation of the power system transfer capability based on voltage and thermal limitations and for security monitoring. The software utilizes State Estimator (SE) and synchrophasor PMU data sets for determining the power system operational margin under normal and contingency conditions. ROSE implementation is based on “hybrid” approach where SE solution (model) is used to compute voltage stability limits, and PMU data (measurements) is used to determine the position of the current operating point. This software allows improving security of transmission system by continuously monitoring operational margin expressed in MW flow or in bus voltage angles, and alarming the operator if the margin violates a pre-defined threshold.