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Showing papers on "Electrical network published in 1984"


Journal ArticleDOI
TL;DR: In this paper, a technique is developed for deriving an equivalent load model to represent the dynamic and steady state effects of a system consisting of induction motors and constant impedance loads interconnected by a network.
Abstract: A technique is developed for deriving an equivalent load model to represent the dynamic and steady state effects of a system consisting of induction motors and constant impedance loads interconnected by a network Motor parameters are calculated from standard specifications, and together with network and load data are incorporated into an admittance matrix which is used to define most of the parameters of the load equivalent The inertia and running slip are chosen to minimize the error between the transient response of the system and its equivalent Step responses are calculated using a state approach Adequacy of the equivalent is validated by comparing the response of the original system and the equivalent to simulated bus voltage change, transformer outage, and remote and local balanced faults using a transient stability program

93 citations


Patent
11 May 1984
TL;DR: An electrical circuit package comprises a stamped and formed lead frame to which is molded a dielectric housing member which includes openings having exposed electrical contacts, the housing member providing support for the lead frame as discussed by the authors.
Abstract: An electrical circuit package comprise a stamped and formed lead frame to which is molded a dielectric housing member which includes openings having exposed electrical contacts, the housing member providing support for the lead frame. Some of the exposed contacts in the openings serve to support electrical components in the openings and to make electrical contact therewith while other of the exposed contacts in the openings electrically engage the electrical components and maintain them in the openings. Further exposed contacts electrically engage another electrical component and the housing member and the further exposed contacts maintain the other electrical component in the housing member. An electrical switch is part of the lead frame.

72 citations


Journal ArticleDOI
TL;DR: In this article, a new technique for interfacing electrical machine models with electromagnetic transients programs is presented, which does not require a Thevenin equivalent circuit of the electrical network.
Abstract: A new technique is presented for interfacing electrical machine models with electromagnetic transients programs. The machine models with their associated controls, loads or turbines can be assembled as subroutines by the user and interfaced to the electrical network or other machine models directly. The machine models employ the standard state variable equations and may use any integration technique for solution. The technique does not require a Thevenin equivalent circuit of the electrical network.

62 citations


Journal ArticleDOI
TL;DR: In this article, a method for reducing computation memory required by Lyapunov' s direct method has been presented, which is applied to transient stability studies of large-scale power systems containing more than 100 generators.
Abstract: In this paper, a method for reducing computation memory required by Lyapunov' s direct method has been presented. This requirement gets critical when the direct method is applied to transient stability studies of large-scale power systems containing more than 100 generators. Firstly, the system equations, the Lyapunov function, and the linear equations associated with the calculation of the stable equilibrium state, have been formulated in such way that the extreme sparcity of the network admittance matrix could be taken advantage of. Secondly, the programming techniques such as optimally ordered triangular factorization and efficient storage scheme of sparse matrices have been introduced. Lastly, the effectiveness of the method has been investigated with the 107-generator and 363-bus power system represented by the detail generator model including automatic voltage regulators ard power system stabilizers.

53 citations


Patent
25 Oct 1984
TL;DR: In this article, a radio receiver is located in the main housing of a remote control toy and a radio transmitter is placed in the remote housing for receiving transmitted radio signals by the radio receiver, and a moving member is associated with the piezoelectric element for generating an electrical current.
Abstract: A remote control toy has a main housing and a remote housing. A radio receiver is located in the main housing for receiving transmitted radio signals. The main housing includes a plurality of elements moveably mounted thereon which are set in motion by a motor in response to receipt of transmitted radio signals by the radio receiver. The remote housing incorporates a radio transmitter. The transmitter includes an electrical circuit having an antenna, a piezoelectric element for generating a current and an electrical component which is capable of generating a radio frequency signal in response to current flow through the electrical circuit. The remote housing further includes a moving member which is moved by the operator of the toy. The moving member is associated with the piezoelectric element to impact a mechanical force on the piezoelectric element for generation of an electrical current in the electrical circuit.

41 citations


Journal ArticleDOI
TL;DR: In this paper, the relationship between general linear programming (LP) and network flow algorithms is described and shown how LP can be made competitive for network problems and applications to fuel scheduling and contingency analysis are discussed.
Abstract: In recent years there has been growing interest in the use of network flow algorithms to solve power system fuel, hydro, and interchange scheduling problems. There have also been attempts to solve electrical power flow problems with related transportation algorithms. The problems solved using network flow or transportation algorithms are naturally linear, or forced into a linear form, and are therefore also amenable to solution by more general linear programming (LP) techniaues. It has been claimed that specialized network flow algorithms are more efficient than general LP for problems which can be expressed in network flow format. On the other hand the use of general LP is attractive, since a considerable amount of information on its application to power systems problems is available. This paper describes relationships between general LP and network flow algorithms and shows how LP can be made competitive for network problems. Applications to fuel scheduling and contingency analysis are discussed.

33 citations


Journal ArticleDOI
TL;DR: In this article, an application of linear programming to transmission constrained generation production cost analysis in power system planning is described, which allows a large electrical network representation to be studied with a detailed load and generation model.
Abstract: This paper describes an application of linear programming to transmission constrained generation production cost analysis in power system planning. The approach allows a large electrical network representation to be studied with a detailed load and generation model. Hour by hour transmission element loadings are calculated and the unconstrained generation dispatch is adjusted to relieve any over- loads for simultaneous pre-contingency and post- contingency limits. A secure dispatch for all hours results from the repeated application of the methodology. The results include annual production costs and cost penalties reflecting the effects of hourly transmission constraints and summaries of overloaded and constraining transmission elements.

31 citations


Journal ArticleDOI
TL;DR: In this article, an improvised algorithm for optimal VARM allocation in a large power system using a linear programming (LP) technique is presented. But the proposed method requires less computer======¯¯¯¯¯¯memory than those algorithms currently available.

25 citations


Journal ArticleDOI
TL;DR: In this paper, the authors describe a simulator study of a four-terminal HVdc system with a small parallel tap and interconnected to an AC network with weak AC systems at the four dc terminals.
Abstract: The paper describes a simulator study of a four-terminal HVdc system with a small parallel tap and interconnected to an AC network with weak AC systems at the four dc terminals. The small tap is rated at 25% of the rating of the HVdc system and the effective short-circuit ratios at the dc terminals are in the range of 2.1 to 3.0. The study includes the transient performance of the dc system for various types of system disturbances, such as AC system faults, dc line faults, and commutation failure at the small inverter.

25 citations


Journal ArticleDOI
TL;DR: This paper presents an iterative pole-removal method based on the least-squares fitting techniq% to synthesize RLC equivalent networks according to their specified driving-point function in the frequency domain.
Abstract: In power system simulation (by means of TNA or digital computer) equivalent networks can be used to reduce the simulation complexity. This paper presents an iterative pole-removal method based on the least-squares fitting techniq% to synthesize RLC equivalent networks according7 to their specified driving-point function in the frequency domain. The synthesized networks are composed of only passive components to represent the DC constant, complex poles as well as poles at zero and infinite. Poles are removed individually from the specified driving-point function applying the least-squares fitting with respect to the frequency domain around the relevant resonance. This algorithm converges quickly even for highly resistive systems.

24 citations


Patent
05 Mar 1984
TL;DR: A circuit breaker connector (100) for joining the ends of a pair of cables (10, 20) and passing an electrical signal therethrough, including a contact arrangement comprising an input contact (38) and an output contact (44) electrically connected to an internal switch contact (70) with the contacts cooperating to define a first electrical circuit path, and make-before-break switch means (72, 60) allowing insertion of an external circuit element (90) without interrupting the first circuit path for completing a second electrical circuit element including the circuit element(90) before
Abstract: A circuit breaker connector (100) for joining the ends of a pair of cables (10, 20) and passing an electrical signal therethrough, including a contact arrangement comprising an input contact (38) and an output contact (44) electrically connected to an internal switch contact (70) with the contacts cooperating to define a first electrical circuit path, and make-before-break switch means (72, 60) allowing insertion of an external circuit element (90) without interrupting the first circuit path for completing a second electrical circuit path including the circuit element (90) before breaking the first electrical circuit path.

Proceedings ArticleDOI
25 Jun 1984
TL;DR: Results indicate that the implementation of a relaxation-based circuit simulation algorithm, called Iterated Timing Analaysis, on a multi-processor has a great deal of potential for reducing the cost of circuit simulation.
Abstract: The electrical circuit simulation of large integrated circuits is very expensive. New relaxation-based algorithms promise to reduce this cost by exploiting the properties of large networks. However, this speed improvement is not sufficient for the cost-effective analysis of very large circuits. While array processors have helped inprove the performance of circuit simulators, further improvement can be achieved by the use of special-purpose multiprocessors. In this paper, the implementation of a relaxation-based circuit simulation algorithm, called Iterated Timing Analaysis, on a multi-processor is described. Initial results indicate that this approach has a great deal of potential for reducing the cost of circuit simulation.

Journal ArticleDOI
TL;DR: In this article, the authors evaluated coordinated active and reactive power modulation for centralized and decentralized DC power modulation and demonstrated that coordinated reactive power modulation not only improves the system damping but also alleviates the mode shifting problem during the modulation.
Abstract: Coordinated active and reactive power modulation is evaluated for centralized and decentralized DC power modulation. Linear analysis and simulation studies are made for different DC network configurations. Simulation studies made on a hybrid computer demonstrate that coordinated reactive power modulation not only improves the system damping but it also alleviates the mode shifting problem during the modulation.

Journal ArticleDOI
TL;DR: In this paper, a new approach has been developed to digitally model the transient response of ac/dc power systems to disturbances, which is comprised of the widely available Electro-Magnetic Transients Program (EMTP) on a mainframe computer operating in parallel with a microcomputer containing a detailed converter control model.
Abstract: A new approach has been developed to digitally model the transient response of ac/dc power systems to disturbances The digital simulator is comprised of the widely available Electro-Magnetic Transients Program (EMTP) on a mainframe computer operating in parallel with a microcomputer containing a detailed converter control model and extensive user-interactive capability A description of the simulator is provided, and examples are given to demonstrate its versatility and to emphasize the importance of detailed control modeling

Patent
24 Dec 1984
TL;DR: In this article, a test apparatus for testing such electrical circuit elements as components of printed circuit boards or integrated circuit chips includes a number of substantially indentical pin modules or units, one for each pin under test.
Abstract: A test apparatus for testing such electrical circuit elements as components of printed circuit boards or integrated circuit chips includes a number of substantially indentical pin modules or units, one for each pin under test. The several modules are separately programmed by a CPU to provide a suitable state at the pin under test, i.e., excitation signal, read signal or impedance. Power to the unit under test is provided by the pin module.

Journal ArticleDOI
TL;DR: In this article, a generalized excitation control design that ensures not only a desired damping of critical electro-mechanical modes of oscillation but also zeroing of the terminal voltage error independent of terminal voltage excursions is presented.
Abstract: This paper presents a generalized excitation control design that ensures not only a desired damping of the critical electro-mechanical modes of oscillation but also the zeroing of the terminal voltage error independent of terminal voltage excursions. The excitation system consists of a compensation transfer function utilizing the machine speed or terminal frequency and/or electrical power. A comparison of the proposed design with a conventional excitation system control indicated its effectiveness in enhancing small scale as well as large scale system stability.

Journal ArticleDOI
TL;DR: In this article, the authors suggest the value of 50 mA direct current as an acceptable level of dc pollution in residential single-phase 120V/240V services, based on experimental measurements carried out on a typical single phase distribution transformer and on an analytical model which considers the flux- magnetizing current characteristic of the transformer.
Abstract: This paper suggests the value of 50 mA direct current as an acceptable level of dc pollution in residential single-phase 120V/240V services. This conclusion is based on experimental measurements carried out on a typical single-phase distribution transformer and on an analytical model which considers the flux- magnetizing current characteristic of the transformer. The response to dc biasing of single-phase motors and transformers used in residential circuits was the key factor in establishing the permissible level of dc injection.

Journal ArticleDOI
TL;DR: In this article, a two-terminal HVDC system model structure for power system stability analysis is presented. But, the model is limited to twoterminal links and the control systems are not modular.
Abstract: This committee report documents two-terminal HVDC system model structures for power system stability analysis. These-models are intended for steady-state and transient stability analysis. The DC system structures are limited to two-terminal links; however, the modularity of the control systems will make extension to multi-terminal systems relatively easy. The modularity of the structure will also facilitate the incorporation of newer control schemes for AC/DC systems.

Journal ArticleDOI
TL;DR: In this article, the authors discuss the principles of relay systems and describe techniques that have been developed in order to evaluate the reliability of the relay devices and also discuss the principle of monitoring and self-checking within the relay to reduce the probability of an undetected dormant failure.

DOI
01 Jan 1984
TL;DR: The paper proposes general criteria for selecting the number of equivalent `T?
Abstract: The paper is concerned with the representation of transmission circuits used in the evaluation of transient phenomena in power-system networks. The paper proposes general criteria for selecting the number of equivalent ‘T’ or ‘π’ sections that are required to fully represent the circuit over the range of frequency of interest. Emphasis is placed on both the accuracy of representation and economical computation.

Patent
09 Feb 1984
TL;DR: In this article, a method of providing lightning protection for non-metallic component structures, aircraft skins, etc. including sandwich-type skins on aircraft where fast removal and easy access is required between components of the lightning protection electrical circuit path.
Abstract: A method of providing lightning protection for non-metallic component structures, aircraft skins, etc. including sandwich-type skins on aircraft where fast removal and easy access is required between components of the lightning protection electrical circuit path. The electrical circuit path between aircraft structures utilizes a flexible clip not requiring fastener connection and removal when a component at the end of the circuit path is required to be replaced.

Patent
21 Dec 1984
TL;DR: The chargeable working light of as discussed by the authors utilizes an electrical circuit to achieve the functions of charging a storage battery from a power source, and alternatively supplying power to a lighting element from the power source and the battery simultaneously.
Abstract: The chargeable working light of the present invention utilizes an electrical circuit to achieve the functions of charging a storage battery from a power source, and of alternatively supplying power to a lighting element from the power source and the battery simultaneously. In addition, the structure of the chargeable working light gives facilities for being adjusted to properly provide illumination from a desired place and direction.

Patent
12 Oct 1984
TL;DR: In this paper, a differential circuit breaker and a pre-circuit breaker are used to cut off the power supply to the electrical assembly when the sensor detects a release of gas.
Abstract: It comprises a differential circuit breaker 2 and a pre-circuit breaker 3 comprising a sensor 7 which is sensitive to the gases liberated by heating in an electrical circuit and creating, when the sensor 7 detects a release of gas, a current leak to earth triggering the differential circuit breaker and cutting off the power supply to the electrical assembly 1

Journal ArticleDOI
G. Opoku1, C. M. Ong1
TL;DR: In this article, a formulation for coordinating all controllable reactive power sources, including the DC converters of a multiterminal DC system, to correct bus voltage violations is presented.
Abstract: The paper presents a formulation for coordinating all controll-able reactive power sources, including the DC converters of a multiterminal DC system, to correct bus voltage violations. Based on the formulation, an algorithm using Linear Programming solution technique has been developed. The effectiveness of this algorithm to correct bus voltage violations in a 30 bus, 5 DC terminal AC-DC system under heavy and light load conditions is demonstrated.

Patent
10 May 1984
TL;DR: In this article, a relief network consists of the parallel circuit of a resistor and a diode and these in series with a capacitor, and the entire relief network is connected in parallel with a periodically switching electrical circuit breaker (control switch).
Abstract: The relief network consists of the parallel circuit of a resistor and a diode and these in series with a capacitor, and the entire relief network is connected in parallel with a periodically switching electrical circuit breaker (control switch); when the control switch becomes blocking, the current flow is conducted via the diode and the capacitor of the relief network for a short time and when the control switch becomes conducting, the capacitor is partially discharged via the resistor in parallel with the diode, the stored energy being usefully transmitted to another point in the circuit.


Journal ArticleDOI
TL;DR: In this paper, the Observation Decoupled Reference vector is considered as a systemwide target to be tracked and approached using a limited number of contr-l devices such as the converter terminals of an overlying HV-DC system.
Abstract: The concept of the Observation Decoupled Reference vector was introduced earlier [1] by the Washington University research group. It was demonstrated [2] [3] that effective system stabilization can be accomplished based on this new concept using purely local information and local action at the generating stations provided control means such as damping resistors or load skipping are available at each generating station. In this paper the Observation Decoupled Reference vector is considered as a systemwide target to be tracked and approached using a limited number of contr-l devices such as the converter terminals of an overlying HV-DC system. The tradeoff is that fast reliable communication between the generating stations and the Control Center are needed. Computations of moderate size are carried out both at the local units and at the Control Center. Very effective system stabilization is demonstrated by large scale simulation. It is believed that this represents the first real solution for using the (multiterminal) HV-DC system to stabilize an associated AC system.

Journal ArticleDOI
TL;DR: The use of the electrical circuit simulation program SPICE2 for performing digital computer simulations of linear and non-linear pharmacokinetic-pharmacodynamic models is described, and its routine usage in elucidating complex research problems is discussed.
Abstract: The use of the electrical circuit simulation program SPICE2 for performing digital computer simulations of linear and non-linear pharmacokinetic-pharmacodynamic models is described. SPICE2 utilizes the principles of network thermodynamics (thermodynamics of electrical circuits). These principles dictate analogy between the conservation laws of chemical reactions and mass transport and Kirchhoff's laws of current and voltage balance, and also prove that Fick's law of diffusion is isomorphous with the conductance form of Ohm's law. Detailed descriptions of program inputs, formats, and options for simulation of linear and non-linear pharmacokinetic-pharmacodynamic systems are provided, with appropriate examples. Single as well as multiple dose simulations (accumulation kinetics and dynamics) are discussed. The advantages of SPICE2 over other available simulation packages, including user-friendliness, ease of operation, versatility, power, and the economy of time and effort afforded, are emphasized. The educational value of SPICE2 as a highly versatile tool for teaching both fundamental and complex pharmacokinetic-pharmacodynamic concepts, as well as its routine usage in elucidating complex research problems, are also discussed.

Journal ArticleDOI
TL;DR: In this paper, a linear transformation is introduced which transforms the state matrix of the sub-systems into diagonal form to enable the use of numerical integration schemes based on difference state equations, which have an elementary form.

Journal ArticleDOI
TL;DR: In this article, Liu et al. extended the Xia-Heydt power flow study algorithm to accommodate nonlinear loads without the assumption of superposition, radial circuitry, or sinusoidal bus voltage.
Abstract: Modern literature on power system harmonic problems, analysis, and solution is mostly of the case history type [1]. When the harmonic signal strength is low, the assumption of sinusoidal bus voltages is usually made, thereby simplifying analysis considerably. Since interest is often restricted to distribution circuits, simple radial circuit configuration is frequently assumed, and band (frequency) limitation of harmonics is also assumed. The proliferation of rectifier and other nonlinear loads, however, particularly in localized regions, suggests a renewed look at harmonic signals, especially at high harmonic content, near resonance, and cases of considerable bus voltage distortion. Xia and Heydt [2-3] have modified the Newton-Raphson power flow study algorithm to accommodate nonlinear loads without the assumption of superposition, radial circuitry, or sinusoidal bus voltage. Grady [7] has extended the Xia-Heydt algorithm to include nonlinear resistive loads (e.g. fluorescent lamps) and zero sequence signals. One of the primary reasons for the increased deployment of nonlinear loads is the successful development of high power semiconductor switching devices. Nonlinear loads are often characterized by either widespread distribution (such as the case in fluorescent lighting loads and electronic loads and such is the potential in the case of electric vehicle loads [4-6]). Also, the use of large industrial rectifiers directly on the subtransmission voltage system is not unusual in applications of large dc motors, electro-deposition installations, and induction furnaces. Static var devices are new electronic localized sources of harmonic signals.