Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Lane Department of Computer Science and Electrical Engineering

Committee Chair

Ali Feliachi.


The objective of this work is robust decentralized control of power systems through excitation systems and Thyristor Controlled Series Capacitors (TCSC). Hence the dissertation consists of two parts. In the first part an algorithm for the design of nonlinear decentralized excitation control is developed based on a feedback linearization technique. Feedback linearization technique is applied in excitation control of each generator to obtain an interconnected system where subsystems have linear system matrices and interconnections are represented by nonlinear terms. Different ways of achieving decentralization are investigated: (1) linear robust control combined with observer decoupled state space; (2) disturbance accommodation control. While linear robust control guarantees the subsystem's stability when the interconnection terms are bounded within certain values, disturbance accommodation control is based on linear models of the interconnection terms. Nonlinear simulations are performed on a three-machine nine-bus power system. The simulation results demonstrate the effectiveness of the proposed methodologies.;In the second part, indices for control signal selection and mode effectiveness and interaction are developed. They are applied in Thyristor Controlled Series Capacitor damping control, which is to improve inter-area oscillation damping over a range of operating conditions, for evaluating local signals.;Two case studies are performed to explain and demonstrate the effectiveness of the proposed methodologies. The first power system is the two-area four-machine inter-area oscillation benchmark system. The second is the western U.S. power system (WSCC).;The uncertainty shown in the case studies in this dissertation are variations of load conditions. It can also be variations of topologies. The damping controller proposed in this dissertation is to use local measurement as input signals. Local measurements can be obtained by phasor measurement units (PMU). The feasibility of these control schemes using PMU should be investigated using discrete control techniques. Meanwhile, the measurement errors, control signal delays are not considered in this dissertation. Further work can take above factors into consideration. (Abstract shortened by UMI.).