Showing papers on "Power-flow study published in 1968"
TL;DR: A practical method is given for solving the power flow problem with control variables such as real and reactive power and transformer ratios automatically adjusted to minimize instantaneous costs or losses by Newton's method, a gradient adjustment algorithm for obtaining the minimum and penalty functions to account for dependent constraints.
Abstract: A practical method is given for solving the power flow problem with control variables such as real and reactive power and transformer ratios automatically adjusted to minimize instantaneous costs or losses. The solution is feasible with respect to constraints on control variables and dependent variables such as load voltages, reactive sources, and tie line power angles. The method is based on power flow solution by Newton's method, a gradient adjustment algorithm for obtaining the minimum and penalty functions to account for dependent constraints. A test program solves problems of 500 nodes. Only a small extension of the power flow program is required to implement the method.
1,575 citations
TL;DR: In this paper, the authors present a reliability calculation method for the generation system that incorporates the frequency and duration of unit outages and includes consideration of the loads, which leads to calculated generation reliability measures which are the availability, frequency of occurence, and mean duration of reserve states.
Abstract: As a goal, the evaluation and computation of electric power system reliability requires that a consistent technique be used for all portions?generation, transmission, and distribution. At present, a number of different methods are used for the generation system, while the frequency and duration of outages seems to be developing as a standard measure for the analysis of the distribution system. This paper and a subsequent one will present a reliability calculation method for the generation system that incorporates the frequency and duration of unit outages and includes consideration of the loads. This method leads to calculated generation reliability measures which are the availability, frequency of occurence, and mean duration of reserve states. These are cumulative states in that they specify system reserve conditions of a given magnitude or less. This paper is concerned with the procedure for calculating the availability, frequency, and outage duration for a number of generating units connected in parallel to form a single system. Numerical data are used to illustrate the technique and make comparisons with other methods.
94 citations
TL;DR: In this article, power oscillations have occurred between the interconnected utility systems of Saskatchewan, Manitoba, and Ontario (West System), such power swings have been most evident when the power transmission angles on the interconnections or on certain internal 138kV and 115-kV transmission have been of relatively great magnitude.
Abstract: Intersystem power oscillations have occurred between the interconnected utility systems of Saskatchewan, Manitoba, and Ontario (West System). Such power swings have been most evident when the power transmission angles on the interconnections or on certain internal 138-kV and 115-kV transmission have been of relatively great magnitude. The oscillations have been controlled or reduced by adjustment of the excitation of speed control parameters on various groups of machines throughout the three inter- connected systems. The analytical techniques utilized to determine the adjustments will be of considerable benefit in planning future exrtensions to the interconnections and facilities within the power systems in the three provinces.
56 citations
TL;DR: In this article, the damping power system swings have been studied by analog and digital simulation, and the authors proposed a damping scheme based on analog simulation and analog simulation techniques.
Abstract: Techniques for damping power system swings have been studied by analog and digital simulation.
38 citations
TL;DR: In this article, a novel approach to the reactive and distortive powers that characterize nonlinear control elements is presented, and it has been proved that these powers may be neutralized when using similar nonlinear elements which, however, are suitably interconnected.
Abstract: Recent developments in energy conversion, including ever increasing use of controlled elements, have created new aspects with regard to power factor considerations. This paper describes and analyzes a novel approach to the reactive and distortive powers that characterize nonlinear control elements. It has been proved that these powers may be neutralized when using similar nonlinear elements which, however, are suitably interconnected.
37 citations
TL;DR: In this article, a new method for finding B coefficients expressing loss in a power system as a function of power input is presented, which takes advantage of the fact that partial derivatives of voltage phase angles with respect to any plant power output are independent of system generation schedules and load levels.
Abstract: A new method is presented for finding B coefficients expressing loss in a power system as a function of power input. The computer program necessary to find these loss (B) coefficients is very simple, and transformations of variables are not required. The method takes advantage of the fact that partial derivatives of voltage phase angles with respect to any plant power output are independent of system generation schedules and load levels, as shown in a previous paper. Many of the usual assumptions in calculating B coefficients are eliminated.
24 citations
Patent•
03 Oct 1968TL;DR: In this article, a regulated electric power system having load and return bus lines is provided, where a plurality of solar cells interconnected in power supplying relationship and having a power shunt tap point electrically spaced from the bus lines are provided.
Abstract: A regulated electric power system having load and return bus lines. A plurality of solar cells interconnected in power supplying relationship and having a power shunt tap point electrically spaced from the bus lines is provided. A power dissipator is connected to the shunt tap point and provides for a controllable dissipation of excess energy supplied by the solar cells. A dissipation driver is coupled to the power dissipator and controls its conductance and dissipation and is also connected to the solar cells in a power taping relationship to derive operating power therefrom. An error signal generator is coupled to the load bus and to a reference signal generator to provide an error output signal which is representative of the difference between the electric parameters existing at the load bus and the reference signal generator. An error amplifier is coupled to the error signal generator and the dissipation driver to provide the driver with controlling signals.
22 citations
TL;DR: A network-flow method is applied for the load-flow calculation in electric power systems and a computer handling technique from the computational aspects is discussed, able to handle calculation rapidly without requiring so large an amount of computer memory.
Abstract: This paper aims to apply a network-flow method for the load-flow calculation in electric power systems and to discuss a computer handling technique from the computational aspects. An attractive feature of the new method is its ability to handle calculation rapidly without requiring so large an amount of computer memory. The program based upon the proposed method has been developed, and a flow diagram for the algorithm is presented. A numerical example for the calculation is also described as well as the convergence characteristics of the solution of computational processes. The method is compared with a conventional one from viewpoints of computation time and data storage space.
13 citations
01 Apr 1968
TL;DR: Partitioning techniques for the nodal-impedance methods of the power-system network load-flow solution are derived and classified and shown how they follow from simple rearrangement of the matrix iterative procedures.
Abstract: Partitioning techniques for the nodal-impedance methods of the power-system network load-flow solution are derived and classified. The techniques include normal matrix inversion using partitioning and successive inverse modification, the topological or diakoptic and the algebraic partitioning principles. The paper shows how, without reference to network graph theory, these principles follow from simple rearrangement of the matrix iterative procedures.
7 citations
TL;DR: In this paper, a method has been developed to simulate an automatic frequency control system in ac-dc power transmission on an analog computer, and three new methods of automatic frequency ratio control (AFRC) by dc transmission are considered and compared.
Abstract: A method has been developed to simulate an automatic frequency control system in ac-dc power transmission on an analog computer. As an example of an ac-dc system a model of Sakuma frequency changer, between Tokyo Electric Power Co. system (50 Hz) and Chubu Electric Power Co. system (60 Hz), is studied in detail. Three new methods of automatic frequency ratio control (AFRC) by dc transmission are considered and compared. The variation of frequencies in the ac systems and the dc power change due to a step load increase in the Chubu power system are examined. These frequency variations and power change are used to optimize the parameters of the AFRC devices.
6 citations
TL;DR: In this article, the power-frequency control of a multimachine power system model is investigated using combined boiler-turboalternator units interconnected with the general node equations of a transmission network.
Abstract: The power-frequency control of a multimachine power system model is investigated using combined boiler-turboalternator units interconnected with the general node equations of a transmission network. The boilers, represented by lumped energy storage elements, are combined with the turbine equations using flow- power relations associated with static operating characteristics. The alternators are represented by a linearized set of Park's equations in a form suitable for investigating the effects of voltage regulator action.
TL;DR: In this article, the broad principles used in the planning of VAR supply and control on the American Electric Power System are described, and the importance of a well planned and coordinated VAR control in the design of a reliable power system is emphasized.
Abstract: The broad principles are described which are used in the planning of VAR supply and control on the American Electric Power System. The discussion relates to the selection, utilization, and coordination of various VAR supply and control equipment, such as generators, synchronous condensers, static capacitors, and shunt reactors. Emphasis is placed on the importance of a well planned and coordinated VAR control in the design of a reliable power system.
TL;DR: A concept of load-frequency control associated with security actions to prevent system disturbances is presented and utilizes a technique based on logic and adaptive circuits.
Abstract: A concept of load-frequency control associated with security actions to prevent system disturbances is presented. It utilizes a technique based on logic and adaptive circuits.
01 Oct 1968
TL;DR: In this paper, the results of a feasibility study to apply state estimation techniques to an electric power system are summarized, where the state estimator is a digital data processing scheme which constitutes the real-time data base from which many of the central control, display, interrogation, monitoring, alarm, and logging functions derive their information.
Abstract: The results of a feasibility study to apply state estimation techniques to an electric power system are summarized. The state estimator is a digital data processing scheme which constitutes the real-time data base from which many of the central control, display, interrogation, monitoring, alarm, and logging functions derive their information. The state estimator, when included in a simulation of the sensing and telemetry subsystems, can also be used off-line to explore the design trade-offs between accuracy and cost of the information subsystem required for power system control.
TL;DR: In this paper, the reverse transfer static inverter and static ac bus transfer switch system, as applied to power generating stations, are discussed and the proper protection methods for branch circuit coordination with static systems are described, using a particular power plant as an example.
Abstract: The reverse transfer static inverter and static ac bus transfer switch system, as applied to power generating stations, are introduced. Equipment for which such protection is required and the power quality necessary are discussed. The proper protection methods for branch circuit coordination with static systems is described, using a particular power plant as an example.