This paper introduces a new nonlinear control of flexible ac transmission systems (FACTS) controllers for the purpose of damping interarea oscillations in power systems. FACTS controllers consist of series, shunt, or a combination of series-shunt devices which are interfaced with the bulk power system through injection buses. Controlling the angle of these buses can effectively damp low frequency interarea oscillations in the system. The proposed control method is based on finding an equivalent reduced affine nonlinear system for the network from which the dominant machines are extracted based on dynamic coherency. It is shown that if properly selected, measurements obtained from this subsystem of machines are sufficient inputs to the FACTS controllers to stabilize the power system. The effectiveness of the proposed method on damping interarea oscillations is validated on the 68 bus, 16 generator system of the New England/New York network.


Electrical and Computer Engineering

Second Department

Computer Science


National Science Foundation (U.S.)


Supported in part by the National Science Foundation under Grant ECCS 0701643

Keywords and Phrases

FACTS; PMU; Coherent Groups; Dominant Machines; Interarea Oscillation; Nonlinear Control; Phasor Measurement Unit (PMU); Wide-Area Control

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 2010 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Oct 2010