Abstract: An online static security assessment (SSA) method based on a quasi steady-state (QSS) model is applied to a power system. An input to the method includes a post-contingency state of the power system for each of a set of contingencies. The following operations are performed for each contingency. Using the QSS model of the post contingency state of the power system, a steady-state voltage magnitude is calculated for each bus in the power system by solving a system of equations. The system of equations is formulated according to a time-domain stability model of the power system and includes nonlinear differential algebraic equations (DAE) with continuous and discreet variables. The derivative terms of short-term state variables in the DAE are set to zero. The method compares the calculated voltage magnitude with a limit, classifies each contingency as secure, critical or insecure, and determines a control action in response to the classification.

Abstract: An online static security assessment (SSA) method based on a quasi steady-state (QSS) model is applied to a power system. An input to the method includes a post-contingency state of the power system for each of a set of contingencies. The following operations are performed for each contingency. Using the QSS model of the post contingency state of the power system, a steady-state voltage magnitude is calculated for each bus in the power system by solving a system of equations. The system of equations is formulated according to a time-domain stability model of the power system and includes nonlinear differential algebraic equations (DAE) with continuous and discreet variables. The derivative terms of short-term state variables in the DAE are set to zero. The method compares the calculated voltage magnitude with a limit, classifies each contingency as secure, critical or insecure, and determines a control action in response to the classification.