Robust var unit control strategies for damping of power system oscillations
This thesis is concerned with the development of var unit control strategies to improve the damping of electromechanical oscillations (0.1 to 2.0 hertz) which commonly occur in power systems. The objective is to use network information, locally available at the var unit bus, to produce a signal that determines the appropriate time-varying susceptance of the var unit. Two strategies, one nonadaptive and one adaptive, are developed. The nonadaptive control strategy is based on a computer-generated linearization of the nonlinear power system model. A fixed-controller design is then obtained using eigenvalue analysis. The adaptive control strategy is based on real-time identification of reduced-order models of the system. An adaptive, linear quadratic, optimal controller is then formulated which determines the var unit susceptance values needed to quickly reduce system oscillations. The effectiveness of each of these control strategies is tested by computer simulation of a nine-bus power system. A detailed explanation of the methods used to simulate power system dynamics are also presented. The simulation results illustrate the potential usefulness of applying these types of controllers to dampen oscillations of large interconnected power networks. The robust character of these controllers is also illustrated.
- Research Organization:
- Montana State Univ., Bozeman, MT (USA)
- OSTI ID:
- 5263992
- Country of Publication:
- United States
- Language:
- English
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