Output Feedback Multivariable Control for an Advanced Boiling Water Reactor

This paper presents a preliminary design of an Output Feedback Multivariable Control for use on an ABWR. Although the design is simple and compact, it meets all the major control requirements for use in load following and frequency regulation in a utility power system. The Multivariable Control coordinates three out of four controls with four measurements and integrals of two of these measurements. The design features dynamic control structure switching with a constant gain matrix; recirculation flow is varied above 70% load demand, while control rods are varied below 70% load demand. This paper describes the 23 state model that was used, the Multivariable Control design, and the nonlinear time domain performance of an ABWR with the Multivariable Control.     

Performance comparison of three identification methods for theanalysis of electromechanical oscillations

This paper describes the results of a study to evaluate the performance of three identification methods for the study of low frequency electromechanical oscillations. The three identification methods considered are: the Steiglitz-McBride algorithm; the eigensystem realization algorithm; and the Prony method. The identification methods are used to identify low order linear systems of power systems modeled in standard transient stability programs. This is accomplished by processing the system response to a simple probing pulse. The frequency domain characteristics of several identified systems are compared using three power systems with lightly damped electromechanical modes     

Damping control design based on time-domain identified models

This paper presents an integrated approach for designing damping controllers for large power systems. First, a low-order model is identified from a time simulation of the nonlinear power system model. Then an exact multi-modal decomposition is used to develop design indices for selecting on appropriate input signal to the controller. The method is illustrated with the design of thyristor-controlled series compensator damping controllers in two test systems     

Power system reduction to simplify the design of dampingcontrollers for interarea oscillations

This paper describes the application of a reduction method to power systems to obtain simplified models that facilitate the design of damping controllers. The reduced system retains the lightly damped swing of interest and exhibits modal characteristics similar to the unreduced system in the frequency range associated with swing modes. A power system damping controller is designed using a reduced system. The modal characteristics of the reduced and unreduced system with the damping controller included, are compared. The validity of the control design is assessed via nonlinear simulations. The reduction method is simple to implement and is based on the computation of the observability and controllability Gramians     

Robust control design of power system stabilizers using multivariable frequency domain techniques

H_∞ and structured singular value optimization techniques are used to design robust power system stabilizers (PSS) for a single-machine and a two-machine system with varying operating conditions. Realistic uncertainty models to represent the possible operating conditions as perturbations from a nominal operating condition are developed. System experience is used to select weighting functions to provide adequate damping and shape the controller frequency response. Computer simulations show that the PSS designed using the proposed technique provides improved damping compared to a conventional PSS.     

Coordinated control of two FACTS devices for damping interareaoscillations

This paper presents the design and application of a simple controller to damp interarea oscillations. The controller coordinates the control action of a thyristor controlled series capacitor (TCSC) and a thyristor controlled phase angle regulator (TCPAR) to allow for increased power transfers with improved system damping. The controller is based on the application of projective controls and coordinates readily available measurements with control signals applied to the FACTS devices     

Functional design for a system-wide multivariable dampingcontroller [for power systems]

A system-wide dynamic controller is designed to improve power system damping. Multivariable control techniques, involving many machines and associated measurements and controls, are applied on a large-scale system with realistic dynamics. An iterative design method with multiple tasks is presented. It uses eigenvector-based dynamic reduction, suboptimal state space control design, reconstitution of design to full system representation, and verification. The resulting hierarchical controller is shown, with time simulations and eigenvalues, to stabilize the system for heavy power transfer without adverse side effects     

Recent applications of linear analysis techniques

This paper is based on material presented at the Panel Session: Recent Applications of Linear Analysis Techniques conducted during the 1998 IEEE PES Summer Meeting. The topics discussed include: control system design; system identification; large scale system applications; simultaneous coordination of power system stabilisers and FACTS controllers; robust power system stabilisation; small signal stability analysis based on time-domain identified models; EM transient studies modal analysis; and power system dynamics nonlinearities, normal forms method     

Application of long-term simulation programs for analysis of systemislanding

This paper describes the main results and conclusions from the application of two different long-term stability programs to the analysis of a system islanding scenario for a study case developed by Red Electrica de Espana (REE), based on the Spanish system. Two main goals were to evaluate the performance of both simulation programs in the long-term stability area, and to analyze the influence of some important control and protection elements (tie-line loss-of-synchronism relays, underfrequency load-shedding, load-frequency control, and power plant dynamics). Conclusions about modeling and computational requirements for system islanding (frequency) scenarios and use of long-term stability programs are presented     

Multiple time-scale power system dynamic simulation

A new program, EXSTAB (extended time-scale stability) has been developed for representing a wide variety of power system performance problems, from transient stability through long-term dynamics and voltage instability. The capability of the program includes multiple execution modes and automatic step size selection to address conflicting goals of accuracy and efficiency. The modeling includes a broad range of apparatus to provide the needed time-scale representation (four orders of magnitude). Models for automatic generation control, plant characteristics and control, voltage and reactive power control, static and dynamic loads, and protective relaying for apparatus and system connections are provided. Technologies were developed to perform analysis of voltage stability and prediction of peak power transfer to avoid voltage collapse