INTRODUCTION

Power-system stability calculations fall into three major categories: transient, steady-state, and voltage stability. Transient stability analysis examines the power-system response to major disturbances, such as faults or loss of generation. This analysis is typically nonlinear and focuses heavily on the ability of the system generators to maintain synchronism. Steady-state stability analysis examines the qualitative nature of steady-state equilibrium in response to infinitesimally small disturbances. This analysis uses a linear version of the detailed dynamic models and focuses on the eigenvalues of the linear system and the response of control systems. In earlier literature, steady-state stability was frequently referred to as dynamic stability. Voltage stability analysis examines the ability of a power system to maintain acceptable voltage levels in response to both abrupt and gradual disturbances. This analysis primarily uses steady-state modeling, although some analysis may consider dynamics of voltage controls such as tap-changing-under-load transformers.

The first procedure presented is the formulation of models that are utilized for stability analysis. Using these modeling techniques, the remaining procedures illustrate both small- and large-scale stability calculations. The small-scale procedures are provided to illustrate the mathematical steps associated with the analysis. The large-scale procedures provide the necessary considerations to perform this analysis on realistic system models.

DYNAMIC MODELING AND SIMULATION

Since power-system stability analysis is based on computations involving mathematical models, it is important to understand the formulation of these models as well...