This report describes an enhanced test system (RTS-96) for use in bulk power system reliability evaluation studies. The value of the test system is that it will permit comparative and benchmark studies to be performed on new and existing reliability evaluation techniques. The test system was developed by modifying and updating the original IEEE RTS (referred to as RTS-79 hereafter) to reflect changes in evaluation methodologies and to overcome perceived deficiencies.

The IEEE Reliability Test System-1996. A report prepared by the Reliability Test System Task Force of the Application of Probability Methods Subcommittee

This paper provides a detailed account of analytical work carried out to determine the parameters of power system stabilizers (PSS) for the Darlington nuclear generating station presently under construction in eastern Ontario. The results presented are, however, of general interest and provide a comprehensive analysis of the effects of the different stabilizer parameters on the overall dynamic performance of the power system. They show how stabilizer settings may be selected so as to enhance the steady-state and transient stability of local plant modes as well as inter-area modes in large interconnected systems. In addition, it is shown that the selected parameters result in satisfactory performance during system islanding conditions, when large frequency excursions are experienced. Darlington GS, when completed by 1992, will comprise four 1100 MVA, 0.85 p.f., 1800 RPM turbine generators with "CANDU-PHW" reactors, moderated and cooled by heavy water. The station will be incorporated into the 500 kV network through three double-circuit lines. The units will be equipped with transformer-fed thyristor excitation systems and Delta-P-Omega type PSS [1, 2].

Application of power system stabilizers for enhancement of overall system stability

The design concept and use of the power system toolbox (PST), a Matlab-based power system dynamics simulation and control design package, are discussed. The motivation for developing the package was to provide a flexible environment for teaching power system simulation techniques and control design concepts to advanced undergraduate and graduate students, and for graduate students to perform research and development on power systems. The authors discuss the capabilities of PST and the software development philosophy. Sample applications are given. Some potential educational usage is suggested. The future enhancement to the package is outlined. >

A toolbox for power system dynamics and control engineering education and research

Efficient algorithms are presented for the solution of two important problems in the area of damping control of electromechanical oscillations in large-scale systems. The proposed algorithms allow the determination of: the most suitable generators for installing power system stabilizers; the most suitable buses in the system for placing static VAr compensators in order to damp the critical modes of oscillation. These algorithms involve the calculation of transfer function residues and represent an important extension of the powerful methodology described by V. Arcidiaconos et al. (see IEEE Trans. Power Apparatus and Systems, vol.PAS-99, p.769-78, 1980), whose use was up to now restricted to power systems of limited size. A major advantage of this methodology is that there is no limitation on the degree of modeling of the power system being studied. >

Determination of suitable locations for power system stabilizers and static VAr compensators for damping electromechanical oscillations in large scale power systems

In this paper, a new approach to adaptive underfrequency load shedding (UFLS), a procedure for protecting electric power systems from dynamic instability and frequency collapse, is presented. It consists of two main stages. In the first stage, the frequency and the rate of frequency change are estimated by the nonrecursive Newton-type algorithm. By using the simplest expression of the generator swing equation, in the second algorithm stage, the magnitude of the disturbance is determined. The UFLS plan is adapted to the magnitude estimated, obtaining in this way a more efficient system operation during emergency conditions. Results of procedure testing are demonstrated through the dynamic simulations by using: 1) a simple three-machine test system and 2) a ten-machine New England system

Adaptive underfrequency load shedding based on the magnitude of the disturbance estimation

A method of analyzing the small signal stability of very large power systems is described. The method is based on a frequency-domain approach which concentrates on the electromechanical modes of the power system under study. By using a modular modeling concept and an efficient sparsity network solution routine, systems having up to 12000 buses and 1000 detailed generator models can be studied. A comparison is made between eigenvalues calculated by this method and by other existing programs. >

Eigenvalue analysis of very large power systems

There is an emerging recognition that utility investments and other decisions that affect electric service reliability should be explicitly evaluated on the basis of their cost and benefit implications. A cost-benefit approach that quantifies the reliability benefits of alternatives in terms of the reduction in costs resulting from unserved energy enables the evaluation of generation and transmission capacity additions on a consistent, economic basis. This approach has been applied to two utility case studies. In a case study for Pacific Gas and Electric Company, it was used to evaluate three options for maintaining reliability in a major load center-two involving local generation, and the third, a new 230 kV transmission connection. In a case study for Duke Power Company, the approach was used to evaluate alternative designs for proposed additions to a transmission station. This paper describes the methodology and presents the two utility studies. >

Cost-benefit analysis of power system reliability: two utility case studies

A new approach is described for assessing the adequacy and security of bulk power systems. The method takes into account generation and transmission failures, load variation, generation economic dispatch, security limits, maintenance schedules, the control actions implemented in emergencies. and the impact of different operating schemes. Reliability indices for generation adequacy, transmission adequacy, and system security are defined. The proposed method is demonstrated by application to the IEEE Reliability Test System (RTS). >

A comprehensive approach for adequacy and security evaluation of bulk power systems

There are two types of energy transactions between electric utilities. Utility A may sell power to utility B because the latter experiences shortage of generation to supply its own load, or utility A has surplus of low cost generation and utility B is willing to buy some power from A to replace its more expensive generation. If utilities A and B do not have direct interconnection, the power has to be "wheeled" through the transmission system of intervening utilities. The purpose of this paper is to describe the mathematical model used in a program to assess the potential for transactions among utilities, taking into account production costs, wheeling charges, load variations and transmission and generation limits. The results are determined by maximizing the profits of all or selected group of companies. An important feature of the model is that each power transaction is broken down in terms of fuel-to-fuel subtransactions where the following information is explicitly identified: 1) selling utility, 2) fuel type used by the selling utility to generate the required power for the sale, 3) buying utility, 4) fuel type of generating units turned down by the receiving utility as a result of the energy purchase. Existing optimal generation dispatch models usually treat an interconnected system as a multi area system where dispatch is optimized on a global basis. As a result of the global system dispatch, certain utilities may end up being dispatched in an uneconomical manner so that global optimality is achieved.

B. Porretta

Papers

Eigenvalue analysis of very large power systems

Cost-benefit analysis of power system reliability: two utility case studies

A comprehensive approach for adequacy and security evaluation of bulk power systems

Optimal economic power transfers