Stability Of Multi-machine Power System Research Articles

Coordinated Synthesis of Multimachine Power System Stabilizer Using an Efficient Decentralized Modal Control (DMC) Algorithm

This paper presents a new method for simultaneously selecting the power system stabilizer (PSS) parameters in multimachine power systems. Design of local output feedback power system stabilizer using local signal of the generator (e.g. speed or power) is formulated as a decentralized modal control (DMC) problem. Exact model reduction based on modal control theory is proposed to make the determination of PSS parameters highly efficient. Results obtained from the coordinated tuning of the parameters of three power system stabilizers equipped on a multimachine power system show that exact assignment of the eigenvalues associated with the poorly damped electromechanical modes can be achieved in a very efficient manner.

Coordinated tuning of proportional-integral power system stabilizers in multimachine power systems

A new method for the coordinated synthesis of proportional-integral power system stabilizers in multimachine power systems is presented in this paper. In contrast to the previous approaches which are iterative in nature, the stabilizer constants are obtained in a single step by solving a set of algebraic equations. This makes the proposed approach much more efficient than other methods. The effectiveness of the proposed algorithm is illustrated by the simultaneous selection of the parameters of three proportional-integral stabilizers in a multimachine power system. It is shown that the eigenvalues associated with the poorly damped electromechanical modes can be exactly assigned to desired locations in a very efficient way.

Efficient Eigenvalue and Frequency Response Methods Applied to Power System Small-Signal Stability Studies

Frequency response and eigenvalue techniques are fundamental tools in the analysis of small signal stability of multimachine power systems. This paper describes two highly efficient algorithms which are expected to enhance the practical application of these techniques. One algorithm calculates exact eigenvalues and eigenvectors for a large power system, while the other produces the frequency response of the transfer functions between any two variables in the system. This paper also presents alternative computing procedures for the AESOPS eigenvalue estimation algorithm which are simpler and at least as efficient as those described in [1].

Coordinated tuning of power system stabilizers in multimachine power systems

In this paper a new approach to simultaneously tuning the power system stabilizer (PSS) settings in a multimachine electric utility system is presented. The approach is based on eigenvalue assignment, which is treated as a problem of solving a set of non-linear equations. The possibility of meeting additional specified performance criteria is discussed. The flexibility of the proposed method is demonstrated using an operating utility system.

Design of stabilisers in multimachine power systems

The paper presents a new method for designing decentralised stabilisers in multimachine power systems. Here the main design objective is to enhance the dynamic stability of a power system by applying powersystem stabilisers with parameters so determined that some or all of the system mechanical-mode eigenvalues have prescribed values. The usefulness of the proposed method is illustrated through numerical examples, including two multimachine power systems.

Pole assignment of a class of multivariable systems using localized dynamic output compensators with prescribed poles

A novel method for stabilizing a class of multivariable systems through pole assignment using decentralized dynamic compensators is presented. The method is particularly useful for designing stabilizers for improved dynamic stability of multimachine power systems; this is illustrated using a numerical example.

Coordinated Synthesis of Power System Stabilizers in Multimachine Power Systems

A new coordinated synthesis method of applying power system stabilizers (PSS) was developed by combining eigenvalue sensitivity analysis and linear programming. This method is simultaneously able to select the generators to which the PSS can be effectively Applied and to synthesize the adequate transfer functions of the PSS for these generators. The proposed itethod is used to synthesize the coordinated PSS for a 12-machine system.

Coordinated Synthesis of Power System Stabilizers in Multimachine Power Systems

Coordinated Synthesis of Power System Stabilizers in Multimachine Power Systems

Torque-angle loops in multimachine power systems

The synchronizing and damping torques are derived from the torque-angle loop of a single machine infinite bus-bar system. This paper uses frequency response methods to generalize the analysis to an n machine system. A transfer function matrix G(s) is derived to relate the n-vector of electrical torques to the n-vector of rotor angles. The characteristic locus method is used to decompose the stability analysis into n torque-angle loops each of which is similar to the torque-angle loop of a single machine infinite bus-bar system. The method is used to analyse the dynamic stability of an uncontrolled multimachine power system. It is shown that the stability can be assessed by the evaluation of a set of eigenvalues of G(0) which can be considered as a set of synchronizing torque coefficients.

Using a frequency method for tuning automatic excitation control parameters

This paper considers a novel approach to tuning the adjustable parameters of stabilizers in multimachine power systems in order to obtain the best dynamic performance. With the proposed technique, the condition for stability of the system and the range of variation of the adjustable gains can be determined. Selection of the appropriate values of excitation system parameters for a multi-machine power system is considered.

Simultaneous optimization of the adjustable parameters in multimachine power systems

This paper considers a novel approach to simultaneous optimization of the adjustable parameters of all the stabilizers in multimachine power systems to obtain the best dynamic performance. It is based on frequency domain analysis using the domain-separation method, Nyquist's stability criterion, and the frequency criterion of quality. With the proposed technique, the condition for stability of the system and the range of variation of the adjustable gains can be determined. In addition, the values of the adjustable parameters can be selected for the best system dynamic response. The method is especially effective for complex system investigations.

Coordinated synthesis of power system stabilizers in multimachine power systems

A new coordinated synthesis method of applying power system stabilizers (PSS) was developed by combining eigenvalue sensitivity analysis and linear programming. This method is simultaneously able to select the generators to which the PSS can be effectively Applied and to synthesize the adequate transfer functions of the PSS for these generators. The proposed itethod is used to synthesize the coordinated PSS for a 12-machine system.

Multimachine stability analysis using vector Lyapunov functions with inertial-centre decomposition

Multimachine power system stability is investigated by means of a new decomposition technique. The power system is decomposed into subsystems using the inertial-centre concept. Individual Lyapunov functions are then obtained for each subsystem. Stability conditions for the overall system are established, taking into account the interconnection characteristics. The least restrictive overall system Lyapunov function is obtained by weighting each subsystem instability is then used to determine the critical clearing time.

Tuning of Stabilizers in Multimachine Power Systems

This paper proposes a novel approach for simultaneously selecting. the parameters of all the stabilizers in multimachine power systems. The parameter optimization problem is cast into an eigenvalue. assignment formulation and. an algorithm enabling exact assignment of selected system modes is presented. The proposed algorithm is used to design the stabilizer loops for a three machine-infinite bus dynamically unstable power system.

Tuning of Stabilizers in Multimachine Power Systems

Tuning of Stabilizers in Multimachine Power Systems

An optimal control to improve transient stability of multi-machine power system

An optimal control to improve transient stability of multi-machine power system

Simple quasioptimal control of excitation for stabilization of multimachine power system

A closed loop quasioptimal excitation control strategy has been developed for a multimachine power system problem. The control is obtained directly as a function of angle, frequency and acceleration of the different synchronous generators of the system. A modification of the control proportional to the switching function is proposed. Response with both bang-bang quasioptimal and proportional control schemes was compared with that of a basic exciter regulator for the multimachine system. It was observed that both feedback strategies are much superior to the basic scheme, the proportional controller being preferable in terms of realization and smooth voltage regulation.

Selection of Parameters of Stabilizers in Multimachine Power Systems

This paper presents a technique for selecting the parameters of stabilizers in multimachine power systems. The technique enables the selection of the parameters of stabilizers such that specified improvements in the damping ratios of the poorly damped modes of oscillation are realized approximately. A numerical example of a multimachine system is presented to illustrate the proposed technique.

On the Analysis and Improvement of the Transient Stability of Multi-Machine Power Systems

On the Analysis and Improvement of the Transient Stability of Multi-Machine Power Systems

On the Analysis and Improvement of the Transient Stability of Multi-Machine Power Systems

The aim of this paper is to show that sufficient conditions for the stability of an N-machine power system can be obtained by considering the stability of N decoupled single machine subsystems. It is also shown that the proposed technique helps in designing decentralized controllers for the N-machine system for improving stability. The results are illustrated numerically for a 3-machine system.