An application of generator units and ULTCs in reactive power management in a large scale power system

One of the most important issues in electricity power systems, regulated or deregulated, is reactive power management. Voltage stability, voltage profile and losses optimization are some of objectives in reactive power management and control. Under Load Tap Changer (ULTC) transformers and generator units are two common instruments which have been used in this regard. In this paper, simultaneous optimization of voltage stability, voltage profile and active losses as a multi objective function is considered. A new method for ULTC and generator candidate selection as well as implementation method in a large scale power system is demonstrated in this paper. In this paper, we introduce a new method for adjusting regulating voltage for selected ULTCs and generators, as well as tap position of ULTCs to achieve optimum voltage stability, voltage profile and losses in the system. After fully explained formulation, we will implement our method on an IEEE standard test system, and then we will apply our method on Iranian large scale power system and will demonstrate the results.