Simultaneous stabilisation approach for power system damping control design through TCPAR employing global signals

Abstract

A robust damping control design methodology for a thyristor controlled phase angle regulator using global signals is proposed based on the simultaneous stabilisation approach. The numerical design algorithm determines the controller parameters in order to guarantee closed-loop poles in the left half plane with preferential treatment to those corresponding to the inter-area modes. Plant models under different operating conditions are incorporated in the design formulation to achieve the desired performance robustness. A three-input/single-output controller is designed for the TCPAR to provide adequate damping to the critical inter-area modes of a study system model. Based on the observability of the inter-area modes, real power flows from remote locations are used as feedback stabilising signals. The damping performance of the controller is examined in the frequency and time domains and is found to be robust against varying power-flow patterns, nature of loads, tie-line strengths and system non-linearities, including saturation

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

“…1) Thus, the optimal state-feedback control law is given by (10) where and is the unique symmetric positive semidefinite solution of the algebraic Riccati equation (ARE) (11) subject to being stabilizable, , , and has no unobservable modes on the imaginary axis [19]. 2) For practical implementation measuring all the states of the plant is infeasible, thus, an estimator (Kalman filter) is employed to provide the required estimates.…”

“…methods received increased attention in power systems [6]- [10], however, issues with weighting function selection make the whole design procedure difficult. Linear quadratic Gaussian (LQG) control approaches using different FACTS devices have been presented for closed-loop identification in [11], [12], and power system stabilizer (PSS) for small systems in [13].…”