Direct Calculation of Line Outage Distribution Factors

Line outage distribution factors (LODFs) are utilized to perform contingency analyses in power systems. Since each contingency requires separate LODFs, a quick calculation of LODFs, especially with multiple-line outages, could speed up contingency analyses and improve significantly the security analyses of power systems. This letter provides two direct proofs for expressing LODFs in terms of power transfer distribution factors (PTDFs) of pre-contingency network. Simple matrix calculations are required in the proposed approach for a fast evaluation of LODFs.