Evaluation of effect of SSSC stabilizer in different control channels on sub-synchronous resonance oscillations

Abstract

To increase transmitted power, series capacitors may be used in the transmission lines. A compensated transmission line together with a turbine-generator may cause sub-synchronous resonance (SSR) phenomena in a power system. In this paper, details of dynamic modeling of a single machine power system connected to the network through a transmission line, compensated with a series capacitor, has been presented. Static synchronous series compensator (SSSC) as one of series FACTS devices has been used for damping of the SSR oscillations. For this purpose, a linear damping SSSC-based stabilizer with lead-lag structure is included to SSSC controller. To determine parameters of SSSC stabilizer, a new multi-objective function has been proposed. In this function, in addition to improve stability of critical modes the gain of the stabilizer has been considered. To have stabilizer with minimum phase structure, suitable constraints have been determined and added to the objective function. To optimize the objective function, a recently developed optimization technique known as grey wolf optimization (GWO) algorithm has been applied. The eigenvalues analysis and nonlinear simulations on the IEEE first benchmark model (FBM) power system with a SSSC stabilizer illustrate the effectiveness of the proposed method to suppress SSR oscillations in the studied system.