Application of STATCOM in Eliminating Subsynchronous Resonance in Power Systems

Abstract

In this paper, a STATCOM is used to damp the subsynchronous oscillation in power systems with long transmission lines compensated by series capacitors. By using a new auxiliary subsynchronous damping controller (SSDC), the STATCOM connected at the transmission line is able to damp the subsynchronous resonance (SSR) caused by disturbances. The torsional modes characteristics of the system are investigated in this paper and a new design method is proposed for the SSDC based on a nonlinear optimization to suppress the torsional modes in a wide range of operating conditions. A proper stabilizing signal is chosen for the SSDC input in order to modulate the reactive current reference of STATCOM in the torsional modes. The IEEE second benchmark is used to study the SSR. The eigenvalue and FFT analysis as well as the transient simulation are used to demonstrate the ability of STATCOM with the proposed SSDC in damping the SSR.