A Fast Approximate Fault Simulation Method for Power Systems Contingency Selection

Anew contingency analysis method for contingency selection is proposed in this paper. In the method proposed, a fault is simulated by power injections to adjacent buses on the fault devices in ａ pre-fault system, and by essentially a non-iterative linear calculation to avoid recalculation of a Z-matrix or refactor of a Y-matrix. As more accurate load flow calculation is available by the method proposed than by the sensitivity approach, more reliable contingency selection is available, even though the computational speed of the method is a little slower than that of the method using the sensitivity approach. From the IEEE 30 bus example, it is found that the method is satisfactorily applied to the contingency selection from the view of both the accuracy and the computational speed. The error of the method is less than 1％ in voltage and less than 1 degree in phase angle for most fault cases of the IEEE 30 bus system. The computational burden is less than 10％ of that of P-Q decoupled load now method in most fault case