Adaptive control design for a synchronous generator

The operating point of a power system changes to an unknown point with an unknown change in the mechanical input power. In this paper, a nonlinear adaptive controller is designed for excitation system of the generator based on the backstepping control technique, in order to achieve transient stability enhancement, in the presence of uncertainties in mechanical power. The designed controller guarantees the convergence of system states to new desired values corresponding to unknown mechanical power. A power system consisting of a synchronous generator connected to an infinite bus through a double circuit transmission line is used in control design and the simulation studies. Computer simulation verifies the effectiveness and the validity of the proposed control, considering faulted system with a clearance and change in network topology. © 2014, Editura Academiei Romane. All rights reserved

Energy-Driven Analysis of Electronically-Interfaced Resources for Improving Power System Dynamic Performance

This dissertation investigates the strengthening of power system dynamics with regard to electromechanical oscillations by using electronically-interfaced resources (EIR). The dissertation addresses (1) the modeling and control design of a flywheel energy storage system and a large-scale solar PV plant. The latest is enabled to participate in oscillation damping control without the need for power curtailment. (2) A new dynamic performance evaluation and coordination of damping controller is also developed to analyze systems with several critically low damping ratios. This is studied by using the system oscillation energy to define the total action and total action sensitivity, which allow the identification of control action that benefit exited modes, rather than fixed targeted modes. Finally, (3) this dissertation proposes a solution for the site selection of EIR-based damping controllers in a planning stage. The effect of wind power variability and correlation between geographically closed wind farms is modeled to analyze the system performance and determine the site selection that maximizes the probability of dynamic performance improvement. Mathematical description as well as simulations in different multi-machine power systems show the advantages of the methods described in this work. The findings of this thesis are expected to advance the state-of-the-art of power system control by effectively and efficiently utilizing the fast power capabilities of EIR in systems with high penetration of renewable energy

Robust nonlinear coordinated control of power systems

To prevent an electric power system losing synchronism under a large sudden fault and to achieve voltage regulation are major objectives in power system design. This paper applies the Riccati equation approach, together with the direct feedback linearization (DFL) technique, to design robust nonlinear controllers for transient stability enhancement and voltage regulation of power systems under a symmetrical three-phase short circuit fault. A DFL excitation controller and a DFL coordinated controller (excitation and fast valving controller) are proposed. The simulation results show that a power system can keep transiently stable, even when a large sudden fault occurs at the generator terminal. The robust nonlinear DFL controllers proposed here can greatly improve transient stability and achieve voltage regulation.link_to_subscribed_fulltex