A Complex Y-Matrix Algorithm for Transient-Stability Study

The algorithm reported here has been implemented on IREQ's Transient Stability program (ST600) since 1980. Its strong convergence allowed many severe disturbances on Hydro-Quebec's system to be properly simulated. No convergence problems directly attributable to the basic algorithm have been observed. The proposed algorithm employs the complex Y-matrix formulation for simplicity, the trapezoidal integration rule for numerical stability, and the simultaneous-implicit approach for the integrity of results, much like the BPA's algorithm. However, its representation of generator dynamics and handling technique for nonlinear loads yield better convergence characteristics.