A New Approximate Load Flow Calculation Method for Contingency Selection

Contingency selection is a necessary part of online contingency analysis. Normally it requires a fast calculation method to approximate load flow results. This paper proposes a mathematical formulation for the efficient implementation of the first iteration of the Newton load flow following a line outage, which takes full advantage of the known factors of the pre-contingency base case Jacobian matrix and the sparsity of nodal power mismatches vectors. Based on it, a new approximate load flow calculation method has been proposed for the selection of single transmission line outage. Although the proposed method is more time consuming than the commonly used 1P-1Q calculation, its accuracy makes it a suitable candidate for applications where post-contingency voltage magnitudes are important or more accurate approximations of load flow results are needed The approach has been demonstrated through simulation results in three standard test systems