Newtonian Steady State Modeling of FACTS Devices Using Unaltered Power-Flow Routines

This paper proposes a Newtonian method for power flow (PF) calculations that incorporates Flexible Alternating Current Transmission System (FACTS) devices, without altering the standard PF routines. The method constructs a criterion function that is external to the PF routine, and which has the property of becoming zero when the FACTS devices are correctly modeled. The external character of the criterion function and the property of becoming zero at the correct solution, are used to form the FACTS-device modeling problem as an external root search, i.e., it occurs externally to the PF. The Newton method is used for the root search, which provides for a Newtonian convergence character of the proposed method, and so, convergence is achieved within a few iterations. By using numerically obtained sensitivities, it is shown that the method easily incorporates different control modes into the modeled FACTS devices-a property that will prove beneficial with the development of smart grids. The method was tested by modeling configurations with single and multiple FACTS devices on the IEEE 14-, the IEEE 300- and the Pegase 13659-bus systems.