Direct Transient Stability Analysis Research Articles

An approach to the direct analysis of transient stability

AbstractThe Transient Energy Function (TEF) method has been intensely investigated over the last decade as a reliable and accurate tool for transient stability assessment of multimachine power systems. In this paper we propose the Potential Energy Boundary Surface (PEBS) based method for direct analysis of transient stability. The critical value of transient energy and the Critical Clearing Time (TCCT) are evaluated without the need for successive calculation and memorization of the system kinetic and potential energy values along the sustained fault trajectory. The method is used for determination of output features in the training phase of the neural‐net based transient security assessment. The proposed approach is tested on the well‐known ten‐generator New England test system demonstrating the validity and accuracy of obtained results.

Application of a modal-based transient energy function to a large-scale stressed power system: Assessment of transient stability and transient voltage dip

In this paper a modal-based transient energy function (MTEF) is used to analyse a large-scale stressed power system exhibiting the inter-area mode phenomenon. The analysis consists of two parts. In the first part, direct transient stability analysis of the inter-area mode is conducted by determining the dominant modes of oscillation involved in the non-linear interaction. Using the machines that have large participation in these modes, relevant disturbed machine groupings are formed. These groupings are then used in the MTEF method for transient stability assessment. In the second part, the MTEF is also used to predict the post-disturbance voltage dip at various buses using an energy based criteria. The developed procedures are tested on a 161-generator coherency-based dynamic equivalent of the Northern States Power system which is part of the Mid-continent Area Power Pool in North America.

Neural-net based calculation of voltage dips at maximum angular swing in direct transient stability analysis

In heavily stressed power systems, post-fault transient voltage dips can lead to undesired tripping of industrial drives and large induction motors. The lowest transient voltage dips occur when fault clearing times are less than critical ones. In this paper, we propose a new iterative analytical methodology to obtain more accurate estimates of voltage dips at maximum angular swing in direct transient stability analysis. We also propose and demonstrate the possibility of storing the results of these computations into the associative memory (AM) system, which exhibits remarkable generalization capabilities. Feature-based models stored in the AM cab utilized for fast and accurate prediction of the location, duration and the amount of worst voltage dips, thereby avoiding the need and cost for lengthy time-domain simulations. Numerical results obtained using the example of the New England power system are presented to illustrate our approach.

Direct analysis of transient stability: Experience with the Taipower system

A direct method for transient stability analysis of a multimachine power system is presented. Emphasis is placed on the detailed development and evaluation of the proposed method in transient stability assessment. An energy-type Lyapunov function, taking into account the effect of transfer conductance, is introduced first. The potential energy boundary surface method is then adopted to determine the critical energy value quickly. The main computational burden in the direct method lies in the reduction of the admittance matrices. In this paper, an efficient reduction technique incorporating the sparsity technique and compensation theory is developed. Finally, the proposed method was tested on the Taipower system, which is the only power system in Taiwan. The results obtained confirm the validity and accuracy of the proposed method, and hence demonstrate the superiority and potential of the direct method in real power system applications.

Sequential transient stability assessment (power system)

A sequential approach to the power-system transient stability assessment is presented and discussed. A reliable modified transient stability criterion is proposed. Simplified transient energy function expressions are derived, which enable a significant reduction of the computation time. The following topics of the direct transient stability analysis method are considered: (1) avoiding the calculation of the stable and unstable equilibrium states; (2) discriminating between several unstable equilibrium states which have close values of the energy margin; and (3) enhancement of the reliability of the stability criterion.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The transient energy function method

The status of the transient energy function (TEF) method of direct analysis of transient stability of power systems is reviewed. The mathematical model is presented; an elementary theoretical basis of the method is introduced; the procedure for using the method in assessing power system transient stability is outlined; and the present condition of the technique and the available computer program is given. The outstanding issues, current development work and new applications are then summarized.

Direct Transient Stability Analysis Using Energy Functions: Application to Large Power Networks

Direct Transient Stability Analysis Using Energy Functions: Application to Large Power Networks

Direct Transient Stability Analysis Using Energy Functions Application to Large Power Networks

This paper deals with the demonstration of the Transient Energy Function (TEF) method in large, realistic power networks. Documented examples of application in power system operation and associated software development for systems up to 228-generators and 1644-buses are given. An overview of the analytical and computational problems encountered in the large scale application of the TEF method is presented. Approaches used to overcome the problems are provided, and the relevant improvements and modifications to the TEF software are discussed.

Analysis of Potential Energy Surfaces of Multimachine Power Systems Using Computer Graphics

This paper reports on undergraduate student involvement in a research project at Iowa State University. The undergraduate project used computer graphics as a tool to investigate the shape of the potential energy surfaces for a multimachine power system. The over-all research project is concerned with the application of the Transient Energy Function (TEF) method in direct transient stability analysis of power systems. The computer graphics used in the undergraduate project are associated with some sophomore-junior level courses. The students used the package in a creative and challenging way to generate information concerning the shape of a function of n-variables (specifically the potential energy), which is difficult to conceptualize. The problem was alleviated by plotting the potential energy with respect to two variables at a time, thus providing a three-dimensional projection of an (n + 1) dimensional surface. The project has provided a better physical insight to a complex analytical problem. It has also given undergraduate students in their junior year a sample of the challenging problems available in the area of computer-aided power system analysis.

A Practical Method for the Direct Analysis of Transient Stability

This paper describes the development and evaluation of an analytical method for the direct determination of transient stability. The method developed is based on the analysis of transient energy and accounts for the nature of the system disturbance as well as for the effects of transfer conductances onsystenmbehavior. It has been evaluated on a 10 generator 39 bus system and on a 20 generator 118 bus system. The method predicts critical clearing times for first swing transient stability which agree very closely with the results of simulations.