Application of Newton optimal power flow to assessment of VAr control sequences on voltage security: case studies for a practical power system

The application of the Newton optimal power flow (OPF) approach to the assessment of VAr controllers on voltage security in the Taiwan Power Company (TPC) is presented in the paper. Important functions in the developed OPF package were achieved to satisfy dispatching requirements. Cases were studied through use of these functions for the purpose of assessing the effect of the various types of VAr controller while considering control sequences. The weakness of traditional OPF packages is pinpointed in that they only obtain an equilibrium solution without the consideration of a proper control sequence. Several significant comments are suggested, on the basis of these results, to set up useful criteria for the security dispatch. A practical 251-busbar system (Taipower) is used to illustrate the test results