STATCOM control of Ill-conditioned power systems using dogleg trust-region algorithm

Abstract

Due to the growing demand for electricity, the power networks are operating close to their stability limits. This motivated power engineers to find cost efficient solutions to the stability problem without going for network extensions. Nowadays, FACTS devices are undergoing a heavy research to check if the use of these devices can solve the control problems in a reliable and economic way. This work investigates the effects of STATCOM devices onto power systems and propose solutions to aroused problems. Mathematical model describing the functionality of STATCOM is derived and four control modes are introduced namely, bus voltage control, reactive power control, STATCOM equivalent impedance control, and remote voltage magnitude control. It is shown that the STATCOM device changes the Jacobian and may force it to become singular leading to an illconditioned power system. Consequently, a more robust method - called trust region Dogleg - is presented to solve ill-conditioned systems. Simulations are performed on the IEEE 14-bus wellconditioned system using the Newton Raphson method and the 11-bus ill-conditioned test system using the Dogleg method.