| This thesis investigates transient stability of the power system using numerical methods and direct methods. Structure preserving models are prepared for the stability analysis, where all nodes in the system are considered. Moreover, frequency dependent loads are modeled to analyze the effect of dynamic loads on the transient stability of the power system. Center of inertia reference frame was used for measuring relative rotor angles. Additionally, Structure preserving energy functions are developed, where all buses of the power system are considered without eliminating buses where current injection are zero and loads are modeled as frequency dependent loads. The structure preserving energy functions developed are used to calculate potential energy, kinetic energy and total energy of the system and stability of the system was predicted by looking at the change in kinetic energy and potential energy. Moreover, the critical clearing time (CCT) was predicted using potential energy boundary surface method (PEBS), where critical clearing time is equal to the time at which total energy is equal to potential energy. Standard IEEE test systems like western system coordinating council (WSCC), New England 39 bus system and NETS-NYPS 68 bus system are used for benchmarking. |
