Showing papers on "Electric power system published in 1980"

Power System Control and Stability

Abstract: Preface.Part I: Introduction.Chapter 1: Power System Stability.Chapter 2: The Elementary Mathematical Model.Chapter 3: System Response to Small Disturbances.Part II: The Electromagnetic Torque.Chapter 4: The Synchronous Machine.Chapter 5: The Simulation of Synchronous Machines.Chapter 6: Linear Models of the Synchronous Machine.Chapter 7: Excitation Systems.Chapter 8: Effect of Excitation on Stability.Chapter 9: Multimachine Systems with Constant Impedance Loads.Part III: The Mechanical Torque Power System Control and Stability.Chapter 10: Speed Governing.Chapter 11: Steam Turbine Prime Movers.Chapter 12: Hydraulic Turbine Prime Movers.Chapter 13: Combustion Turbine and Combined-Cycle Power Plants.Appendix A: Trigonometric Identities for Three-Phase Systems.Appendix B: Some Computer Methods for Solving Differential Equations.Appendix C: Normalization.Appendix D: Typical System Data.Appendix E: Excitation Control System Definitions.Appendix F: Control System Components.Appendix G: Pressure Control Systems.Appendix H: The Governor Equations.Appendix I: Wave Equations for a Hydraulic Conduit.Appendix J: Hydraulic Servomotors.Index.

Homeostatic Utility Control

Abstract: Distribution Automation and Control (DAC) systems have potentially major effects on costs, social impacts, and even on the nature of the power system itself, especially as dispersed storage, generation, and customer interaction become more prevalent. However, at the present time, it is not clear which particular modes of control will best exploit the capabilities of DAC. Homeostatic Utility Control is an overall concept which tries to maintain an internal equilibrium between supply and demand. Equilibrating forces are obtained over longer time scales (5 minutes and up) by economic principles through an Energy Marketplace using time-varying spot prices. Faster supply-demand balancing is obtained by employing "governor-type" action on certain types of loads using a Frequency Adaptive Power Energy Rescheduler (FAPER) to assist or even replace conventional turbine-governed systems and spinning reserve. Conventional metering is replaced by a Marketing Interface to Customer (MIC) which, in addition to measuring power usage, multiplies that usage by posted price and records total cost. Customers retain the freedom to select their consumption patterns. Homeostatic control is a new, untried concept. It is discussed in this paper because its great potential makes it a vehicle for interesting discussions of where the future may actually evolve.

Power System Observability: A Practical Algorithm Using Network Topology

Abstract: A power system is observable if the measurements made on it allow determination of bus voltage magnitude and angle at every bus of the network. This paper outlines the theoretical basis for an algorithm for determining observability. Based on this theory, an algorithm for networks containing both bus injection and line flow measurements is presented.

Coordinated Application of Stabilizers in Multimachine Power Systems

Abstract: This paper addresses the problem of the most effective selection of generating units to be equipped with excitation system stabilizers in multimachine systems which exhibit dynamic instability and poor damping of several inter-machine modes of oscillation. Practical means have been developed using eigenvalue analysis techniques to guide the selection process. The linear state space matrix is derived directly from perturbation of the states of a large scale power system dynamic simulation and a subset of this matrix is used to yield the sensitivity of damping ratios of eigenvalues to stabilization measures in individual machines.

Studies on Power System Load Flow Equivalencing

Abstract: This paper reviews the principles and main methods for load-flow equivalencing, with due emphasis given to on-line applications. Unreduced Load Flow, Ward, REI, Linearization, and Identification methods are covered, introducing a number of new ideas and versions. A critical analysis of the properties of the different methods is made, to assist in choosing the most suitable ones for practical application.

Network Constrained Reactive Power Control Using Linear Programming

Abstract: The use of linear prograrming (LP) in power system reactive power control calculations is presented in this paper. Ihe method incorporates the usual reactive power control devices and is particularly successful in rescheduling tap-changing transfornmers. Solutions are constrained within limits set by busbar voltage levels and network reactive power flows. Results are given which indicate a high degree of reliability and versatility, with solution times which are suitable for real-time applications on large systems.

Multiterminal HVDC Power Systems

Abstract: Papers published over a 17 year period, on the concept of extending 2-terminal HVdc transmission to multiterminal systems, are reviewed. In classifying the contributions, the design and performance expectations are discussed and the prospects for applications are evaluated. Reference is also made to the implications of dc interrupting switches. A comprehensive bibliography is included.

Power System State Estimation: Detection of Topological Errors

Abstract: The applicability of state estimation has been extensively explored and generally accepted by industry. This paper presents a method that greatly enhances the capability of state estimators by considering the presence of errors in the network configuration of the model used. The method is simple, fast and applicable for real-time processing. Results of simulations of various types of topological errors are included.

Harmonic Pollution on Power Systems - A Change in Philosophy

Abstract: Static power converters have increased in number and uses in the past decade, and there has been an increased use of static power capacitors for improving power factor. These two trends have set, the stage for possibly uncontrolled harmonic resonances on industrial power systems. Some example of some problems are given and some practices are recommended, in line with a new IEEE standard, that will minimize the chance of harmful resonant conditions.

Optimal Generation Scheduling of Hydrothermal Power Systems

Abstract: In this paper decomposition and coordination techniques are applied to minimize the operation al cost of hydrothermal power systems. Through this for muXation large systems are dealt with by a more general and precise model that includes thermal operation costs and hydroelectric power generation as nonlinear functions, water head variations, stochastic load demands, hydraulic networks with cascade plants, time delays, and spilling. An economic interpretation and an example are given.

Costs incurred by residential electricity consumers due to power failures

Abstract: A theoretical framework for measuring residential outage costs is presented and empirically tested using the results of a survey of household electricity consumers in the city of Cascavel, Brazil. The results of the Cascavel survey confirm that the chief outage cost imposed on residential users is the loss of a leisure during evening hours. The mean income earning rate for a household is used as an acceptable monetary measure of the marginal leisure loss due to an outage. For example, on this basis, in 1976, a typical electricity using household in Cascavel with an annual income of Cr$60,000 would have to pay only Cr$57 more per annum to reduce the incidence of evening outage by 50 percent. When outage costs are weighted according to the linearly diminishing marginal utility of income, outage costs per kilowatt decrease with increasing income. The major advantage of this method for estimating the leisure costs of outages to residential consumers is its reliance on relatively easy to obtain income data. The equations for the derivation of outage costs are appended. 15 references.

Control for an electrical generating and distribution system, and method of operation

Abstract: A control for an electrical generating and distribution system utilizing a plurality of interconnected microprocessors. An electrical system, for an aircraft for example, may have two engine driven generators and an auxiliary power unit generator with loads connected to each of the engine driven generators through generator circuit breakers. An electrical distribution bus connected through bus tie breakers interconnects the load circuits and the auxiliary generator so that any one generator can power either or both loads. Each generator has a microprocessor generator control unit responsive to the associated generator conditions to control generator operation. A microprocessor bus power control unit is responsive to distribution circuit conditions and correlates information from the generator control units, contributing to operation of the bus tie breakers, controlling distribution of power from the generators to the loads. Serial data links between the bus power control unit and each of the generator control units provide for communication of input and control information and enable comparison of redundant circuit information enhancing reliability of the system operation. A generator voltage regulator utilizes the microprocessor of the generator control unit to develop an error voltage which is added to the average phase voltage of the generator, controlling the generator field current. In the event of a phase failure the generator control unit senses an abnormally high phase voltage condition, disables the average phase voltage circuit and the regulator continues to operate with the error voltage.

Multipower electrical system for supplying electrical energy to a house or the like

Abstract: A multipower electrical system is disclosed for supplying electrical energy to a house. In one embodiment of the invention utility company power is connected through a switch system to a 100 AMP main connected to the home and also to a timer. The timer controls an AC generator which is used to charge a battery system. The battery system in turn drives a 100 AMP dynamotor which supplies power to the 100 AMP main through the switch system. The battery driven dynamotor is employed as the primary source of power. In another embodiment of the invention a 100 AMP generator with a D.C. to A.C. converter supplies electrical energy to the 100 AMP main of the house through a switch system. The 100 AMP generator is driven with energy from either a battery system, a four cylinder engine, a solar system or a wind system powered turbine. The solar system, wind system and four cylinder engine are also used to charge the battery system. Energy is also supplied to the 100 AMP main and the battery system from utility company power, when needed.

Steady State Network Equivalents for Power System Planning Applications

Abstract: Steady State equivalents are of importance for the study of the static characteristics of a large power system when either the computer facilities are limited or the solution time must be decreased. Several equivalents are examined and compared. Emphasis is placed on the REI (Radial Equivalent Independent) equivalencing technique and some practical considerations with regard to its implementation will be discussed.

A New, Fast Technique for Load-Flow Solution of Integrated Multi-Terminal DC/AC Systems

Abstract: The paper describes a new technique for the load-flow calculations of integrated ac/dc systems. The technique is fast, efficient and reliable and is therefore an improvement over known procedures. The representation of dc system is such that it leads to simplifications in calculations and saving in storage requirement and yet it is so ; eneral that a multi-terminal dc system of anyconfiguration and control characteristics can be easily simulated. The procedure uses fast decoupled load flow method, handles all ac/ dc equations simultaneously, and fully exploits the sparsity techniques. The paper shows application of the technique on two systems, one with a point-to-point dc transmission and the other with a 3-terminal mesh HVDC sub-system.

Evaluation and Improvement of Electromechanical Oscillation Damping By Means of Eigenvalue-Eigenvector Analysis. Practical Results in the Central Peru Power System

Abstract: To eliminate oscillatory instability in electric power systems by inserting stabilizers, it is important to have available analytical criteria for the choice of the most suitable generators to which to put the stabilizing feedbacks, and for defining the most convenient parameters for them, without resorting to simulation. Applying some properties of control systems it is possible to set up digital programs based on calculations of eigenvalues and eigenvectors that solve these problems satisfactorily. The report then shows application of the procedures thus defined to a practical case of instability, and field test results that confinn the elimination of instability.

Reserve power supply for computers

Abstract: A reserve power supply for providing backup power to a computer system includes a first battery and a second battery which are switchably interconnected in series or parallel by a switch means. When the batteries are connected in parallel they may be charged by a primary power supply which normally drives the computer system. When the batteries are connected in series they provide power to the computer when the primary power supply fails. This association with the primary power supply and the computer system is effected by a coupling circuit of the reserve power supply. The reserve power supply further includes an indicator circuit which visually and audibly signals when the batteries are providing power to the computer system. The reserve power supply further includes an electrical circuit which connects the voltage from one of the batteries to a second voltage output of the primary power supply and a second voltage input of the computer system. This electrical circuit also converts the voltage from the one battery into a plurality of other voltages for use by the computer system.

Methods and apparatus for maximizing and stabilizing electric power derived from wind driven source

Abstract: The shaft of a wind turbine is connected to the rotor of a three-phase AC generator. The rotor windings, in turn, are connected to the rotor windings of a DC-energized, AC exciter via a differential frequency-converter. A frequency-detector, which monitors the output of the AC generator, is connected to the input of the frequency-converter to maintain the output of the generator at 60 Hz. A "real" power sensing circuit, connected to the output of the generator, develops a control signal which, when subtracted from a second control signal generated by a power management control circuit, maintains the power output of the generator at the maximum possible level for each particular power output from the wind turbine which drives the generator.

Hierarchical stability and alert state steering control of interconnected power systems

Abstract: A state-space model of an interconnected power system having both generator and load nodes is proposed. The resulting system of equations is interpreted as the degenerate limit of a singularly perturbed system. The model is used to derive a condition for the (local) asymptotic stability of an equilibrium. This condition decomposes in an intuitive way for subsystems interconnected via a backbone network. The model is used to formulate the problem of steering the power system from a postdisturbance alert state to a secure state, and a solution to the steering problem is also proposed.

Fast Detection and Identification of Islands in Power Networks

Abstract: Two algorithms fur the determination of network connectivity and detection of islands in a power system are presented. Both algorithms are tested on a number of typical power systems. Effects of node ordering and matrix storage methods on the computation time are studied for both algorithms and the results are compared. Each algorithm proved to be more suitable under certain conditions. The results show both algorithms to be very fast. The connectivity of a 115 substation power system is determined in less than 25 milliseconds on a small industrial computer using the new algorithms.

Simulation of Arc Furnace Power Systems

Abstract: An electronic arc model has been developed which simplifies the study of harmonic phenomena in are furnace power systems on a transient network analyzer (TNA). The model helps insure the proper magnitude and phase relationship of the harmonies at each loading condition. The simulation procedures and arc model characteristics are described. Also, some examples of typical study results are given.

Summary of an IEEE Guide for Power-Line Carrier Applications

Abstract: The document described in this summary provides general guidance covering the use of power-line carrier n North America. The goal of the Guide is to provide application information to users of carrier equipment as applied to power transmission lines. Information related to the expanding usage of carrier on distribution lines is not specifically covered; however, brief descriptions are given of carrier applied over media other than direct coupling to overhead power lines. These include power cables, intrabundle channels, and insulated shield wires.

Coordination of Load Conservation with Turbine-Generator Underfrequency Protection

Abstract: A system disturbance or operating abnormality may leave a power system with a generation deficiency, which, if uncorrected, can result in an extensive power outage. The possibility of such disturbances has led to increased interest in the application of automatic underfrequency protection schemes to restore load/generation balance and to prevent equipment damage. This paper presents a comprehensive underfrequency protection program recently developed for the Southern electric system in which digital computer simulations were used to optimize a system- wide load shed program and to verify its coordination with a steam turbine-generator underfrequency protection scheme.

Electric utility demand limiting device and method

Abstract: An electric utility demand limiting device and method for disconnecting and reconnecting a load, such as a residential customer load, from a utility company power system. The device may include a preset demand limit against which power consumption is compared when the device is remotely enabled in response to a remote control signal from the utility company. The demand limit may be variable.

Dual alternator feedback system

Abstract: In an emergency vehicle, a feedback system for dual alternators employed to charge two batteries and wherein one battery is employed to supply power for the vehicle chassis electrical system and the emergency equipment load is supplied with power directly from the outputs of the two alternators. A separate regulator is provided for each alternator for regulating the voltage applied to its alternator. The output of each alternator is connected to the input of its regulator by way of a diode.

Benefits of Voltage Scheduling in Power Systems

Abstract: This paper concerns itself with the utilization and the coordination of reactive sources and other voltage control equipment in system operations. The reactive sources specifically considered are: generators, synchronous condensers, switched static capacitors and shunt reactors, and transformers with and without load tap changing capabilities. The paper presents a methodology for determining the benefits that can be achieved in the proper scheduling of these sources in a power system. The benefits as shown are: savings in fuel production costs, unloading of the system equipment, improved system security, and improved voltages over the system. From a large system study conducted, it appears that these benefits can be obtained with only minor modifications in present scheduling procedures.