Node Breaker Model Based Transient Stability Simulations Including Protective Devices Modeling and Time Coordination

Modeling protection devices in the Transient Stability Assessment (TSA) of power system results in an accurate estimation of system stability and behaviour. Substation (SS) configurations and associated circuit breaker operations which depend on the relay algorithms are usually ignored in TSA. Miss coordination/miss-operations of the relays and CBs result in higher order contingencies, $> N-1$. This needs manual fabrications in Bus-Branch (BB) models used in TSA which can be eliminated by using Node-Breaker (NB) models. Also, incorporating relay algorithms to mimic the realistic CB operations and coordinating their timings increases the complexity of the TSA code for large systems. This paper uses Sparse Tableau Approach (STA) to represent the system in NB model. It provides algorithms for the placement of differential, distance and under/over frequency relays with associated CB operations. It also gives a logic to coordinate timings between relays and CBs. The simulation results demonstrating the effectiveness of the proposed framework are provided for WECC 9 bus, New England 39 bus and Polish 2383 bus systems along with simulation time. The results for WECC 9 bus system are compared and validated with commercial software PSSE.