Showing papers on "Power system simulation published in 1979"
TL;DR: A linear programming method for security dispatch and emergency control calculations on large power systems is presented, which works directly with the normal power-system variables and limits, and incorporates the usual sparse matrix techniques.
Abstract: A linear programming (LP) method for security dispatch and emergency control calculations on large power systems is presented. The method is reliable, fast, flexible, easy to program, and requires little computer storage. It works directly with the normal power-system variables and limits, and incorporates the usual sparse matrix techniques. An important feature of the method is that it handles multi-segment generator cost curves neatly and efficiently.
396 citations
01 Feb 1979
TL;DR: This paper is a critical tutorial-review of the calculation methods used routinely or investigated for use by the industry and concentrates on solution concepts and computational techniques rather than on the analysis of the numerical methods.
Abstract: Engineers in the power industry, face the problem that, while stability is increasingly a limiting factor in secure system operation, the simulation of system dynamic response is grossly overburdening on present-day digital computing resources. Each individual response case involves the step-by-step numerical solution in the time domain of perhaps thousands of nonlinear differential-algebraic equations, at a cost of up to several thousand dollars. A high premium is thus to be placed on the use of the most efficient and reliable modern calculation techniques. This paper is a critical tutorial-review of the calculation methods used routinely or investigated for use by the industry. It concentrates on solution concepts and computational techniques rather than on the analysis of the numerical methods. Details of system modeling are only emphasized when they affect the choice of solution method. The paper concludes with a view of the state of the art and a prediction of future directions of development.
305 citations
TL;DR: The main contribution is a simple extension to the Ward-type equivalencing method that solves the boundary-bus designation problem and gives reliable and accurate results.
Abstract: Equivalent models for the external system in online load-flow studies are presented. The main contribution is a simple extension to the Ward-type equivalencing method that solves the boundary-bus designation problem and gives reliable and accurate results. The method can be applied equally well for off-line equivalencing, where it overcomes the need for buffer zones. Variations on this technique are investigated. The models require topology information, but no real-time measurement data, for the external system. The new methods have been verified by simulation on the IEEE 30 and 118 bus load-flow test systems and on the 835-bus interconnected 15 GW power system of S.E. Brazil.
139 citations
15 May 1979
TL;DR: The paper attempts to provide some clarification of the main fundamental analytical and computational, issues involved in the design of an LP-based method for the rescheduling of power-system operation.
Abstract: Linear and related programming methods have application in transmission planning, security dispatch and emergency control of power systems. With a large still-growing body of literature on the subject, this paper offers a short review of the available LP approaches, techniques and formulations, with due emphasis on state-of-the-art versions. The differences between primal and dual methods and sparse and nonsparse formulations are exposed, and various important techniques such as relaxation, upper bounding and separable programming are dealt with. Thus the paper attempts to provide some clarification of the main fundamental analytical and computational, issues involved in the design of an LP-based method for the rescheduling of power-system operation.
107 citations
TL;DR: In this article, an extension of the power transfer capacity calculation to the calculation of maximum power system loading is described. But the authors focus on the application to assessment of network adequacy and long range planning.
Abstract: This paper describes an extension of the power transfer capacity calculation to the calculation of maximum power system loading. This loading capability is a function of the generation and transmission capacity of the power system. The dc power flow equations provide a basis for the development of constraint equations necessary in the linear programming optimization of the generation-transmission system. An example is provided to illustrate the concepts of the load supplying capability of the power system, and the application to assessment of network adequacy and long range planning is discussed.
75 citations
TL;DR: A new method is presented to calculate the synchronizing and damping components of electrical torque developed in a synchronous machine with arbitrary complexity of machine and control configuration using a least squares error criterion.
Abstract: A new method is presented to calculate the synchronizing and damping components of electrical torque developed in a synchronous machine with arbitrary complexity of machine and control configuration. The individual contributions of field, damper, and reluctance components are determined explicitly. The method is based on numerical analysis of system time responses using a least squares error criterion. The method is equally applicable to responses obtained from on-line measurements or system simulation.
61 citations
01 Jan 1979
TL;DR: This paper describes several formulations of the so-called “simulation/optimization” problem, including constrained optimization and multiple-objective optimization, and describes several procedures for obtaining a solution, including a direct search technique, a first- order response surface method, and a second-order response surface approach.
Abstract: Mathematical programming techniques can be combined with response surface experimental design methods to optimize simulated systems. A computer simulation model has controllable input variables x i , i=1,…, n and yields responses η j , j=1,…, m. A simulation trial at a particular set of values x i k , i=1,…n produces an estimate y i k for the system response η j . This paper describes several formulations of the so-called “simulation/optimization” problem, including constrained optimization and multiple-objective optimization. It also describes several procedures for obtaining a solution to this problem, including a direct search technique, a first-order response surface method, and a second-order response surface approach. Each of these techniques combines simulation, response surface methodology, and mathematical programming.
50 citations
TL;DR: In this paper, the authors describe a theoretical basis and supporting experimental evidence from tests performed at a power plant, for tuning power system stabilizers using frequency response techniques, where the tie-line power was used as a feedback signal to the stabilizer.
Abstract: During the past ten years a number of authors have put forward techniques for tuning power system stabilizers (PSS) in the literature. Some of these techniques have been tested in on-site applications and others have been evaluated using simulation techniques. This paper describes a theoretical basis, and supporting experimental evidence from tests performed at a power plant, for tuning power system stabilizers using frequency response techniques. By using the method described in this paper, the power system analyst is able to obtain an approximate measure of the amount of damping that can be expected from the stabilizer in damping out tie- line power oscillations. The tests were conducted on the inter- tie between the Alberta and British Columbia Hydro power pools. Test results indicated a direct correlation between the improvement in the electric power damping as observed by field tests and that predicted by theoretical means. Although the method suggested in this paper has general application to power system stabilization for local mode damping and inter- tie damping it was applied to the specific case where the tie- line power was used as a feedback signal to the stabilizer.
38 citations
TL;DR: An efficient and reliable algorithm is developed for studying the load shedding and generation reallocation problem in emergencies where a major portion of the transmission system is disabled and an a.c. power flow solution cannot be found for the over- loaded system.
Abstract: An efficient and reliable algorithm is developed for studying the load shedding and generation reallocation problem in emergencies where a major portion of the transmission system is disabled and an a.c. power flow solution cannot be found for the over- loaded system. The problem is first formulated as a nonlinear optimization problem, and an approximation based on a linear sensitivity between real injections and voltage angles is derived. The linearized problem is solved by a linear programming algorithm which exploits the sparsity of the linear programming tableau. The sparse linear programming algorithm is described, and the test result on a 37-node system shown. The solution algorithm is applicable for large networks.
32 citations
15 May 1979
TL;DR: This paper will assess the applicability of vector processors to power flow and transient stability simulation programs and will indicate how these pro- grams should be organized to run efficiently on these new machines.
Abstract: A true technological explosion has taken place in the computer hardware industry in the last few years. Words such as parallel processing, vector processors, array processors, pipelined machines, "number crunching", and megaflops (Millions of FLoating-point OPerations per Second) are heard regularly. Computer manufacturers have responded to the needs of specific groups requiring, above all else, high speed arithmetic capability. The result is a host of new machines which are called in this paper "vector processors". This paper will assess the applicability of vector processors to power flow and transient stability simulation programs and will indicate how these pro- grams should be organized to run efficiently on these new machines. The approach taken will be to survey the entire class of vector processors available now and in the near future, to attempt to raise the reported low efficiency of sparsity-coded programs for large vector processors by reorganizing their sparse structure, and to show how the most time-consuming parts of power system simulation can be "vectorized" for these machines.
23 citations
TL;DR: This paper will assess the applicability of vector processors to power flow and transient stability simulation programs and will indicate how these programs should be organized to run efficiently on these new machines.
TL;DR: In this paper, a comparative test approach is taken by running a series of tests on the AEP Transient Stability Program and on the MIT Physical Scale Model facility which closely approximates actual system dynamic performance characteristics.
Abstract: The adequacy of digital models of synchronous machines in conventional transient stability programs has been of continuing interest and concern to engineers involved in system planning and operating studies. To verify the adequacy of such models a comparative test approach is taken by running a series of tests on the AEP Transient Stability Program and on the MIT Physical Scale Model facility which closely approximates actual system dynamic performance characteristics. The paper summarizes the results of these studies and shows good correlation between the two simulations. Also, the results confirm the findings of others that existing models and associated parameters may need to be improved for certain types of dynamic performance studies and operating conditions.
15 May 1979
TL;DR: This paper examines the possibility of using a dedicated multiprocessor network to do the step-by-step computations needed in the digital simulation of the dynamic response of a large power system.
Abstract: This paper examines the possibility of using a dedicated multiprocessor network to do the step-by-step computations needed in the digital simulation of the dynamic response of a large power system. This multiprocessor network would use a general purpose digital computer for the input and output. It is found that over 97% of the computations for a typical 1723-bus, 396-machine, stability study could be done in parallel. Approximately 30% of the computation time is spent solving the network equations, I = YE. Various algorithms for this part of the solution and ways of scheduling the work assignments to the processors are discussed.
15 May 1979
TL;DR: In this paper, a digital computer program that employs a novel, fast and efficient technique to solve transient stability problems of large scale power systems is presented, which has the unique features of simulating generalized HVDC schemes; and different types of static reactive power compensators, as well as other conventional components in a power system.
Abstract: This paper presents a digital computer program that employs a novel, fast and efficient technique to solve transient stability problems of large scale power systems. The program has the unique features of simulating generalized (two and multi-terminal) HVDC schemes; and different types of static reactive power compensators, as well as other conventional components in a power system. Results for a complex ac/dc multimachine system under low short circuit ratio conditions are presented.
TL;DR: It turns out that no method is able to determine in an acceptable amount of time the optimal unit commitment, so a hierarchical approach is proposed to solve this optimization problem.
04 Sep 1979
TL;DR: Comparison to a broadcast interprocessor communication scheme indicates that this approach outperforms the broadcast scheme in meeting the communication requirements typically found in simulation problems requiring solution of a large system of differential equations.
Abstract: Summary This paper describes a new, high-speed interprocessor communication mechanism for interconnecting up to 256 processing elements in a multiprocessor used for simulation and related applications. The method exploits the iterative computing requirements of this class of problems. It uses parallel buses in conjunction with address-mapping memories to attain high effective interprocessor transfer rates and efficient use of processingelement address space during the problem-solving phase of a simulation study. problem set-up operations and user interaction with the simulated system. Comparison to a broadcast interprocessor communication scheme indicates that this approach outperforms the broadcast scheme in meeting the communication requirements typically found in simulation problems requiring solution of a large system of differential equations. It also supports
15 May 1979
TL;DR: The paper describes an integrated interactive computer package for power system analysis ("POWSYS") that was developed at the Electricity Supply Commission (South Africa) and has been used extensively by its planning and operating engineers for a number of years.
Abstract: A number of digital computer programs are currently available for power system studies. These programs are being used to model networks of increasing size and complexity and the provision of effective data management facilities has become crucial to their successful implementation. The paper describes an integrated interactive computer package for power system analysis ("POWSYS"). This package was developed at the Electricity Supply Commission (South Africa) and has been used extensively by its planning and operating engineers for a number of years. The package features a common file structure of network data and results which is accessed by a set of power system analysis programs. These programs provide the major digital simulation capabilities required to study the behaviour of power systems under both steady state and transient conditions. A simple free-format command language enables the user to control the sequence of studies interactively and to utilize the built in data management and reporting facilities provided. The package is open-ended and the addition of new commands and analysis programs is easily accomplished. The paper will describe the main features and facilities afforded by the data management software and will giveabrief overview of the analysis programs currently implemented.
TL;DR: A method based on "situation recognition" and high speed simulation for on-line security computations is proposed and analyzed that combines the advantages of high speed hybrid computer simulation and pattern recognition methods, and has the flexibility of a pure digital simulation.
Abstract: The operation of large power systems places an increasing importance on the security of the system which must be evaluated in steady state, transient, and long term dynamic situations. A method based on "situation recognition" and high speed simulation for on-line security computations is proposed and analyzed. The method combines the advantages of high speed hybrid computer simulation and pattern recognition methods, and, at the same time, has the flexibility of a pure digital simulation.
15 May 1979
TL;DR: In this article, the authors present results of research sponsored by EPRI on long term power system dynamics conducted by General Electric under contract RP764-2 with support from Southern Company Services, Inc. The simulation of the disturbance was compared to disturbance records and a good match over a two minute period was obtained between the records and the simulation results.
Abstract: This paper presents results of research sponsored by EPRI on long term power system dynamics conducted by General Electric under contract RP764-2 with support from Southern Company Services, Inc. An analysis of a major power system disturbance was made by digital computer simulation of the interacting dynamics of power plants, electrical transmission systems, and connected customer loads. The incident under examination occurred on Tuesday morning, August 7, 1973 in the southern Alabama and Mississippi and western Florida portions of the Southern electric system and resulted in the formation of an electrical island. The seven minute simulation of the Gulf Coast area electrical island was made to: 0 Test and validate the computer program LOTDYS, 0 Explore the effect of alternate simulation data to improve the accuracy of the simulation, 0 Provide further insight and information on this specific incident, 0 Identify and make improvements in analytic methods and data acquisition and estimation methods. The simulation of the disturbance was compared to disturbance records and a good match over a two minute period was obtained between the records and the simulation results. This match was obtained by use of conventional electrical system data supplied by Southern Company Services and typical data for load and prime mover characteristics obtained from a prior EPRI long term dynamics project.(l) In the period after one minute of island operation, the effects of steam plan safety valves and boiler fire trip and restart were found to be significant; LOTOYS was modified to add models of these effects in order to obtain a match to plant pressure chart records. In the period following the first two minutes of the island operation, operator actions and changes in connected customer load were found to be significant; a fair match was obtained by incorporating assumed manual run back of generation and assumed values of load pickup rate.
15 May 1979
TL;DR: The convenient features of the Continuous Systems Modeling Program (CSMP III) in developing of three-phase power system dynamic performance are presented and a modified large resistor interface between the synchronous generator and the network is developed.
Abstract: This paper presents the convenient features of the Continuous Systems Modeling Program (CSMP III) in developing of three-phase power system dynamic performance A modified large resistor interface between the synchronous generator and the network is developed A method of computing the initial conditions of the machie including the more common situation of unbalanced conditions at the generator terminals is suggested The necessary mathematical models of the synchronous generator and the various power system network components are provided for completness Examples of load rejection and single-pole switching applications are included to demonstrate the simulation capabilities using CSMP III
01 Mar 1979
TL;DR: This paper will assess the applicability of vector processors to power flow and transient stability simulation programs and will indicate how these programs should be organized to run efficiently on these new machines.
TL;DR: In this article, a load model for the generation and transmission expansion problems and operations scheduling problems such as long term regulation of hydro, maintenance scheduling, and unit commitment is proposed for use in such problems.
01 Jan 1979
TL;DR: This paper will assess the applicability of vector processors to power flow and transient stability simulation programs and will indicate how these programs should be organized to run efficiently on these new machines.
Abstract: A true technological explosion has taken place in the computer hardware industry in the last few years. Words such as parallel processing, vector processors, array processors, pipelined machines, "number crunching", and megaflops (Millions of FJoating-point Eerations per Second) are heard regularly. Computer manufacturers-have responded to the needs of specific groups requiring, above all else, high speed arithmetic capability. The result is a host of new machines which are called in this paper "vector processors". This paper will assess the applicability of vector processors to power flow and transient stability simulation programs and will indicate how these programs should be organized to run efficiently on these new machines. The approach taken will be to survey the entire class of vector processors available now and in the near future, to attempt to raise the reported low efficiency of sparsity-coded programs for large vector processors by reorganizing their sparse structure, and to show how the most time-consuming parts of power system simulation can be "vectorized" for these machines.