Improvements in sparse matrix/vector technique applications for online load flow calculation

Several analytical and computational improvements in sparsity applications are discussed. A novel partial matrix refactorization method and ordering algorithm are presented. The method is very efficient when applied to programs such as online load flow, optimal power flow, and steady-state security analysis. It is applied in a fast decoupled load flow program which includes the treatment of tap violations on underload tap changing transformers and reactive power generation on PV buses. The effects of proposed improvements are tested and documented on a 118-bus IEEE test network and two utility networks with 209 and 519 buses, respectively.