  The ground truth for cascading failure in power system can only be obtained
through a detailed dynamic model involving nonlinear differential and algebraic
equations whose solution process is computationally expensive. This has
prohibited adoption of such models for cascading failure simulation. To solve
this, we propose a fast cascading failure simulation approach based on implicit
Backward Euler method (BEM) with stiff decay property. Unfortunately, BEM
suffers from hyperstability issue in case of oscillatory instability and
converges to the unstable equilibrium. We propose a predictor-corrector
approach to fully address the hyperstability issue in BEM. The predictor
identifies oscillatory instability based on eigendecomposition of the system
matrix at the post-disturbance unstable equilibrium obtained as a byproduct of
BEM. The corrector uses right eigenvectors to identify the group of machines
participating in the unstable mode. This helps in applying appropriate
protection schemes as in ground truth. We use Trapezoidal method (TM)-based
simulation as the benchmark to validate the results of the proposed approach on
the IEEE 118-bus network, 2,383-bus Polish grid, and IEEE 68-bus system. The
proposed approach is able to track the cascade path and replicate the end
results of TM-based simulation with very high accuracy while reducing the
average simulation time by approximately 10-35 fold. The proposed approach was
also compared with the partitioned method, which led to similar conclusions.
