A Study on LQG/LTR Control for Damping Inter-Area Oscillations in Power Systems

IEEE Trans. Automat. Contr.

2012

Abstract-An arbitrary subset (n − m) of the (n) closed loop eigenvalues of an n th order continuous time single input linear time invariant (LTI) system is to be placed using full state feedback, at pre-specified locations in the complex plane. The remaining m closed loop eigenvalues can be placed anywhere inside a pre-defined region in the complex plane. This region constraint on the unspecified poles is translated into an LMI constraint on the feedback gains through a convex inner approximation of the polynomial stability region. The closed loop locations for these m eigenvalues are optimized to obtain a minimum norm feedback gain vector. This reduces the controller effort leading to less expensive actuators required to be installed in the control system. The proposed algorithm is illustrated on a linearized model of a 4-machine, 2-area power system example.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Partial Pole Placement with Controller Optimization

Datta

IEEE Trans. Automat. Contr.

2012

“…Here such a controller is designed using linear quadratic regulator (LQR) approach [26] based on a 10th order reduced model of the nominal power system.…”

Section: Case Studymentioning

confidence: 99%

An Architecture for FACTS Controllers to Deal With Bandwidth-Constrained Communication

IEEE Trans. Power Delivery

2011

Self Cite

Abstract-Bandwidth constraints could have adverse impact on the flexible AC transmission system (FACTS) controllers relying on signals communicated from distant locations. An observer driven system copy (OSC) architecture is adopted here to deal with low data rates caused by the limited bandwidth availability. The basic idea is to use the knowledge of the nominal system to approximate its actual behavior during the intervals when data from the remote phasor measurement units (PMUs) is not available. This is corrected whenever the most recent states are obtained from the reduced order observer at the PMU location. The closed-loop behavior deteriorates as the operating condition drifts away from the nominal. Nonetheless, significantly better response is achieved under limited bandwidth availability as compared to the conventional approach of communicating the measured outputs. The deterioration is quantified in terms of the difference between the nominal and the off-nominal condition. (e-mail: n.chaudhuri@imperial.ac.uk, b.chaudhuri@imperial.ac.uk Index Terms-

“…The CF receives the constant value of the last available sample during the inter-sample interval in the form of a zero-order hold. Here the controller is designed using linear quadratic regulator (LQR) approach [26] based on a 5th order reduced equivalent of the nominal system.…”

Section: B Control With Cf and Pc Approachesmentioning

confidence: 99%

Damping Control in Power Systems Under Constrained Communication Bandwidth: A Predictor Corrector Strategy

IEEE Trans. Contr. Syst. Technol.

2011

Self Cite

Abstract-Damping electromechanical oscillations in power systems using feedback signals from remote sensors is likely to be affected by occasional low bandwidth availability due to increasing use of shared communication in future. In this paper, a predictor corrector (PC) strategy is applied to deal with situations of low feedback data rate (bandwidth) where conventional feedback would suffer. Knowledge of nominal system dynamics is used to approximate (predict) the actual system behavior during intervals when data from remote sensors are not available. Recent samples of the states from a reduced observer at the remote location are used to periodically reset (correct) the nominal dynamics. The closed-loop performance deteriorates as the actual operating condition drifts away from the nominal dynamics. Nonetheless, significantly better performance compared to conventional feedback is obtained under low bandwidth situations. The analytical criterion for closed-loop stability of the overall system is validated through a simulation study. It is demonstrated that even for reasonably low data rates the closed-loop stability is usually ensured for a typical power system application confirming the effectiveness of this approach. The deterioration in performance is also quantified in terms of the difference between the nominal and off-nominal dynamics. (e-mail: n.chaudhuri@imperial.ac.uk, b.chaudhuri@imperial.ac.uk Index Terms-Damping