Detection of Jacobian singularity and network islanding in power flow computations

The paper provides a tool to investigate the occurrence of Jacobian singularities in power flow computations by Newton methods. In particular, a numerical procedure is presented that establishes the rows or columns of the Jacobian matrix that are linearly dependent. The method proposed is straightforward and may be easily implemented as an extension of any existing factorisation routine. Although the results presented are general, attention is focused on the detection of network islanding in the base case power flow or following a branch outage: the buses belonging to an island are identified at the cost of only one backward substitution computation. Examples of application of the procedure are shown with reference to a small network. Tests were successfully carried out using medium and large scale systems.