Damping SSR in a series compensated power system

In this paper, a new static VAr system (SVS) control scheme for damping torsional modes due to subsynchronous resonance (SSR) in a series compensated power system has been developed. The proposed scheme, called as the Narendra Kumar-subsynchronous resonance (NK-SSR) damping scheme, utilizes the effectiveness of combined reactive power and frequency (CRPF) SVS auxiliary controller in coordination with an induction machine-damping unit (IMDU) coupled to the T-G shaft. The studies are conducted on the first IEEE benchmark model. The scheme stabilizes all the torsional modes over a wide operating range of power transfer. The digital computer simulation study, using a nonlinear system model exhibits a remarkable improvement in the system transient performance. The optimal location of IMDU along the T-G shaft has been determined by performing eigen value analysis. It is found that locating IMDU after the IP turbine yields the maximum damping effect