TCSC-firing angle model for optimal power flow solutions using Newton's method

A novel power flow model for the thyristor-controlled series compensator (TCSC) is presented in this paper. The model takes the form of a firing angle-dependant, nodal admittance matrix that is then incorporated in an existing optimal power flow (OPF) algorithm. Comprehensive OPF solutions of TCSC-upgraded power networks are achieved via Newton's method. The thyristor's firing angle, a newly introduced state variable in OPF formulations, is combined with the nodal voltage magnitudes and angles of the power network in a single frame-of-reference for unified, iterative solutions. This load flow TCSC model advances current models on two counts: (i) it takes full account of the loop current present in the TCSC under either partial or full conduction operating modes; (ii) only compensation regions lying outside the TCSC resonant bands are considered by the OPF solution. This new model is a more efficient counterpart than an existing TCSC controllable reactance model [1]Fuerte-Esquivel C.R., Acha E. A newton-type algorithm for the control of power flow in electrical power networks. IEEE Trans Power Deliv 1997; 2(4):1474–1480.