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Power Systems, IEEE Transactions on

Issue 4 • Date Nov 1992

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Displaying Results 1 - 25 of 27
  • Power system steady state security analysis using vector processing computers

    Page(s): 1451 - 1455
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    The main difficulties encountered in applying a vector processor to the solution of a power flow is the sparsity of the power flow matrices which results in very short vectors when the nonzero terms are gathered into a packed vector format. The authors describe a steady-state security analysis code which overcomes the problem of very short vectors. The length of the list of outages is the major problem in security analysis since it usually includes at least each individual piece of equipment taken one at a time, and a large number of cases with multiple outages. The use of contingency selection and screening has opened the way to reducing this burden, but a very large number of individual cases must be run to satisfy the need to be sure that no cases have gone unchecked. The efforts described have extended the computational speed with which this can be accomplished, and the implementation of very high performance security analysis codes has been made possible View full abstract»

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  • A personal computer based interactive software for power system operation education

    Page(s): 1591 - 1597
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    The use of personal-computer-based interactive software to aid instruction in power system operations is described. The software was designed to be used as a teaching aid for the course power system operation at National Taiwan University. The main programs included in the package were short-term load forecasting and unit commitment. Other supporting routines included power flow analysis, static security assessment, small signal stability analysis, and transient stability analysis. To promote the students interest in the course, a user-friendly interface and interactive windows have been developed. The integrated software package proved to be useful for educational and research purposes View full abstract»

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  • Electricity tariffs under imperfect knowledge of participant benefits

    Page(s): 1471 - 1482
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    The authors consider the problem of establishing tariffs for electrical energy under uncertainty about the value of the energy to the participants. A tariff update that achieves welfare maximization asymptotically through successive approximations to the ideal tariff is proposed. The successive update of the tariff avoids the need for accurate a priori knowledge of electricity system demand and generation as a function of price. The key results are a tariff update algorithm and a proof of local convergence, two necessary steps for implementation of practical responsive pricing View full abstract»

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  • Power engineering industry interaction at Clemson University

    Page(s): 1584 - 1590
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    The authors present a successful model of industry/university cooperation in establishing a strong power system curriculum in both the graduate and undergraduate level. Numerous long-term and short-term research projects have been developed to satisfy the university mission and to tackle challenging problems facing the power industry. A unique structure for the Clemson University Electric Power Research Association (CUEPRA) has been established to promote electric power system research and to meet the need for a working communication link between the power industry and the academic community. The power industries involvements in the power program at Clemson University and the strategic improvements that have been accomplished in research and education are outlined View full abstract»

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  • A Gauss-Markov load model for application in risk evaluation and production simulation

    Page(s): 1493 - 1499
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    Load uncertainty contributes to system operational risk; thus the study of system operating reserve or unit commitment risk requires a load model that includes the uncertainty in load as well as the variation with time. The authors propose a Gauss-Markov load model. This random process model includes both the time variation and the uncertainty in load. This load model is used to predict, conditional on what is known at a previous hour, the mean and the variance of the system hourly load. This mean and variance are required for a system operating reserve study and a broad spectrum of production simulations. The proposed load model is described, the model is justified, and the model is illustrated via an example View full abstract»

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  • A class of models for load management application and evaluation revisited

    Page(s): 1435 - 1443
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    The problem of load modeling for demand side management (DSM) purposes is addressed. The proposed load models rely on information about both the physical characteristics of elemental load devices at the distribution level and usage statistics of these devices. Although the class of models discussed has been previously proposed in the literature, its suitability for DSM purposes is definitely established by showing how the models can be a tool for real DSM actions evaluation. Some results are shown View full abstract»

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  • Overvoltage control during restoration

    Page(s): 1464 - 1470
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    During the early stages of restoring high-voltage overhead and underground transmission lines, the authors discuss three related overvoltage areas: sustained power frequency overvoltages, switching transients, and harmonic resonances. During restoration certain line-transformer configurations when energized generate a combination of sustained, transient, and harmonic overvoltages which may cause surge arrester failures and thus system faults. or the subsequent flash-over and damage to equipment. The energy stored in long high-voltage lines is large causing significant transient or resonant overvoltages which must be carefully considered during restoration. With the help of analytical tools such as the electromagnetic transients program (EMTP) and those described it should be possible to establish general procedures and restoration guidelines to avoid overvoltages View full abstract»

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  • Long range peak demand forecasting under conditions of high growth

    Page(s): 1483 - 1486
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    An extended logistic model with a varying asymptotic upper bound for long-range peak demand forecasting is described. The model has been applied to a typical fast growing system, the Saudi Consolidated Electric Company. The forecasts are compared with actual demands and with those obtained from classical forecasting methods. The model gave relatively accurate peak demand forecasts compared with other classical methods. The model with a single load observation is capable of producing several peak demand forecasts corresponding to different levels of maximum temperature and various levels of social activity. The forecasts produced by the model were also stable irrespective of the length of the ex-post simulation period View full abstract»

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  • Industry-sponsored student projects to promote power quality education

    Page(s): 1550 - 1558
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    The authors present the results of two industry-sponsored senior design projects on power quality: effect of harmonic current distortion on power transformer capability, sponsored by the Philadelphia Electric Company (PECO); and power quality survey of a commercial system, sponsored by BCM engineers. The objective of the first project was to investigate the effect of harmonic current distortion on the capabilities of critical power transformers that service computing equipment in the corporate headquarters of PECO. The objective of the second project was to conduct a power quality survey of the BCM system to ascertain whether power line disturbances were the causes of outages and failures of essential BCM computing facilities. Each project had its own power line monitor. The success of these student projects has promoted interest in power engineering as a career for many of the group members and generated enrollment in the senior-level power program View full abstract»

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  • A novel electric power laboratory for power quality and energy studies: training aspects

    Page(s): 1571 - 1578
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    The laboratory described can examine issues in power quality (PQ) with regard to both stand-alone devices and their behavior in the power system. A project justification which identifies PQ problem areas is presented. Historical backgrounds of both PQ and laboratories in general are provided, to give a brief educational tutorial in the area, and to set the stage for bringing into creation a lab which addresses correctly the needs of industry and students. Development aspects of the lab are presented. This is followed by a description of the testing capabilities of the laboratory that are needed to address the PQ problem areas, along with the laboratory's presentation of results and training/educational capabilities. Aspects of how the laboratory is used cooperating with other facilities are examined so that broader PQ problems can be studied View full abstract»

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  • Impacts of time-of-use rates on the optimal sizing and operation of cogeneration systems

    Page(s): 1444 - 1450
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    For customers with a cogeneration system (CGS), a mixed-integer programming and nonlinear programming model was used to examine effects of time-of-use (TOU) rates on the optimal operation of the constituent equipment as well as the optimal sizing. Three customers were selected for case studies: a hotel, a hospital, and an office building. Effects of an on-peak/off-peak energy charge ratio on purchased power share in the total electricity demand were saturated at the ratio of 5. As the energy charge ratio was raised, cheaper off-peak power substituted for city gas and the operating cost decreased. The responses of the hotel and the hospital were similar. The simulation results indicated that properly designed TOU rates can provide commercial customers an incentive to operate a CGS with an appropriate mix of self-generation and commercial power View full abstract»

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  • New approaches in power system restoration

    Page(s): 1428 - 1434
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    Power system restoration issues are considered. The authors explore some of the possibilities that are opening up for more power system restoration strategies and practices. The areas analyzed include system-wide coordination and overall organization of restoration, expert systems for power system restoration, and operator training simulators in power system restoration View full abstract»

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  • Use of a graphical user interface approach for digital and physical simulation in power systems control education: application to an HVDC transmission system model

    Page(s): 1598 - 1603
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    The authors present the design of a laboratory with software and hardware structures for digital and physical simulation in the area of power systems control education. The hardware structure includes a physically based model of the power system. The software structure includes a special man-machine interface designed with a graphical user interface approach. This interface allows the user full control over the simulation and provides facilities for the study of the response of the simulated system. This approach is illustrated with the design of a control system for a physically based high-voltage DC transmission system model View full abstract»

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  • A Monte Carlo method for multi-area generation system reliability assessment

    Page(s): 1487 - 1492
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    The authors present a method for multiarea generation system reliability assessment. It is based on direct sampling of generating unit states, the clustering technique, and the correlative normal distribution sampling technique of the load states. A linear programming model was used to minimize the total load curtailment. Area load uncertainty, correlation between area loads, and generating unit derated state were considered. Incorporation of these factors does not create a significant increase in computing time. Sensitivity indices of both system and each area to area generation and tie line capacities can be calculated. These indices provide information regarding which tie line or which area generating capacity should be reinforced from the overall system and each area point of view. Calculation results of a four-area system are given to demonstrate the effectiveness of the method View full abstract»

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  • Impact of synchronous machine constants and models on the analysis of torsional dynamics

    Page(s): 1456 - 1463
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    The authors investigate the impact of synchronous machine parameters and second-order and third-order models on the phenomenon of torsional dynamics. The results were compared with those obtained from the conventional (2d, 1q) model. For each model, the effect of rotor-field differential leakage flux on the damping of the torsional oscillations is studied. Numerical values of the elements corresponding to each model were obtained based on a parameter fitting process to a set of stand-still frequency response (SSFR) test results. An eigen analysis method was used for the studies. The eigen analysis results were verified by digital time-domain simulation, using the electromagnetic transients program (EMTP) View full abstract»

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

    Page(s): 1559 - 1564
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    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 View full abstract»

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  • Special considerations in power system restoration

    Page(s): 1419 - 1427
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    Power system restoration issues are considered. The authors discuss a number of particular problems that require special attention in the development of system restoration plans. The areas analyzed include excessive alarms during restoration, switching during restoration, underground transmission system concerns, and telecommunication capabilities and limitations View full abstract»

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  • Electric power engineering education resources 1989-90-IEEE Power Engineering Society Committee report

    Page(s): 1611 - 1622
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    The subcommittee report is based on the eleventh biennial survey of power engineering education resources in the US and Canada. This survey was conducted to determine the electric power engineering education resources available in ABET (Accreditation Board for Engineering and Technology) accredited engineering programs in the US and Canada for the 1989-90 academic year. The report is limited to colleges and universities that replied to a questionnaire. For the 102 colleges and universities that submitted data on their power programs, the report contains a list of faculty active during the 1989-90 academic year, their level of academic participation, and their professional experience. Statistics are also presented on student enrollments at the graduate level, degrees granted, and research funding. A tabulation of graduate and undergraduate electrical engineering power courses and their enrollments offered by each responding university is presented View full abstract»

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  • Computer aided instruction of rotating electric machines via animated graphics

    Page(s): 1579 - 1583
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    A menu-driven interactive graphics software package has been developed for use as an instructional aid for the electric machines course in the electrical engineering curriculum. The main purpose of this tool is to give the students a clearer understanding of the basics of the operation of rotating electric machines. The animation program was developed for displaying live and rotating diagrams depicting different modes of operation of synchronous generators. Different parts are identified with different colors. The interaction of the magnetic poles on the stator and on the rotor, and the relative spatial positions and time variations of the magnetic and electric quantities are demonstrated through moving images. The software features are described View full abstract»

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  • A program of computer-aided coordination analysis for an undergraduate course in protective relaying

    Page(s): 1543 - 1549
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    The authors introduce a program used as a tool for protective relaying courses at the undergraduate level. This program allows students to practice protective devices coordination in power systems on a personal computer by representing the time-current curve with dynamic computer graphics. The program is provided with a debugging system that is designed to inform the user of any problem found in a protection scheme. To make students fully understand the dynamic performance of protective devices coordination, the program allows students to assign the location of a fault, and will display the operating time of the protective devices according to the tripping sequence. The program also has the function of automatic coordination analysis, the results of which can be compared with the user's scheme and can also help the user to have a better understanding of what is actually used in industry today View full abstract»

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  • Undergraduate courses on power system protection at subtransmission and distribution levels

    Page(s): 1604 - 1610
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    The authors present two practical undergraduate-level courses on power system protection: protective relaying, an introductory course which is offered at Drexel University, and overcurrent protection of industrial/commercial power systems, which is offered at Widener University. The first course is a hands-on introduction to the operating characteristics and protection requirements of time overcurrent, directional time overcurrent, and distance relays at the subtransmission level. The second course is an introduction to the analytical techniques and protection requirements for the selection and coordination of overcurrent protective devices for industrial and commercial power systems View full abstract»

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  • Voltage stability evaluation using modal analysis

    Page(s): 1529 - 1542
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    The authors discuss the voltage stability analysis of large power systems by using a modal analysis technique. The method computes, using a steady-state system model, a specified number of the smallest eigenvalues and the associated eigenvectors of a reduced Jacobian matrix. The eigenvalues, each of which is associated with a mode of voltage/reactive power variation, provide a relative measure of proximity to voltage instability. The eigenvectors are used to describe the mode shape and to provide information about the network elements and generators which participate in each mode. A simultaneous iteration method, which is well suited to applications involving large power systems, is used for selective calculation of appropriate eigenvalues. Results obtained using a 3700 bus test system are presented illustrating the applicability of the approach View full abstract»

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  • A decomposition approach to nonlinear multi-area generation scheduling with tie-line constraints using expert systems

    Page(s): 1409 - 1418
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    The authors propose a rigorous method to treat multiarea generation scheduling with tie line limits. An expert system was used for obtaining the initial solution. As the generation scheduling problem involves unit commitment and economic dispatch, the method adopts an iterative procedure to deal with these two phases. The hourly load demand and the area power generation will cause the tie flows to change. To maintain the operation security in every area, the spinning reserve should comply with the area power generation rather than its load demand. After economic dispatch, it is necessary to adjust the unit commitment in each area for preserving the spinning reserve requirements. Heuristics were used to modify the generation unit combinations. The objective is to find an economic generation schedule for a multiarea system. The interchange transactions among areas represent the transportation problem, embedded within the nonlinear optimization process. The equivalent system concept is adopted, and the transmission losses are included in this study. A four-area system with each area consisting of 26 units was used to test the efficiency of the proposed algorithm View full abstract»

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  • A stochastic approach to small disturbance stability analysis

    Page(s): 1519 - 1528
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    A systematic approach to the construction of stochastic models of electric power systems for small disturbance stability analysis is presented. In this study, the cumulative effects of small-magnitude random fluctuations of electrical loads are considered as sources of eventual loss of stability, and a security measure is derived to determine the small-disturbance stability limits of the stochastic system. The electric power system models were tested on a 30-bus power system and compared according to the relative effects of load fluctuations on the proposed security measure View full abstract»

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  • COPERITE-computer-aided tool for power engineering research, instruction, training and education

    Page(s): 1565 - 1570
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    A graphics-oriented, primarily PC-based tool for education, research, and training in power engineering is introduced. The tool, called COPERITE, has all user interfaces resident on an IBM-386 microcomputer. Menus and windows are used for the interface, and attractive graphical representations and displays are included. Application programs that are interfaced are power flow, contingency analysis, economic dispatch, security-constrained dispatch, system stability, and fault analysis. These programs are executed on a VAX 8800 computer mainly for speed of execution. Information exchange between the PC and the VAX is made through an Ethernet connection which is transparent to the user. Results of execution show on the graphical front-end accessible to the user. COPERITE has a powerful network editor with the capabilities of adding, deleting, moving, and finding symbols with a graphics cursor. Provisions are present for building and using artificial intelligence techniques for system operation enhancement View full abstract»

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Aims & Scope

Covers the requirements, planning, analysis, reliability, operation, and economics of electric generating, transmission, and distribution systems for general industrial, commercial, public, and domestic consumption.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Antonio J. Conejo
The Ohio State University