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Showing papers on "Electrical network published in 1999"


Journal ArticleDOI
TL;DR: In this article, an efficient and robust three phase power flow algorithm for application to radial distribution networks is presented. And the proposed method has been tested to analyse several practical distribution networks of various voltage levels and also having high R/X ratio.

235 citations


Journal ArticleDOI
TL;DR: The drawbacks of existing neural networks have been overcome in the generalised neuron structure which has been developed to control the deviations in load frequency of a power system.

224 citations


Journal ArticleDOI
TL;DR: In this paper, a method of calculating available transfer capability and the exploration of the first order effects of certain power system network variables are described and quantification of these network uncertainties can provide information necessary for system operation, planning and energy market participation.
Abstract: A method of calculating available transfer capability and the exploration of the first order effects of certain power system network variables are described. The Federal Energy Regulatory Commission has ordered that bulk electrical control areas must provide to market participants a "commercially viable" network transfer capability for the import, export and throughput of energy. A practical method for deriving this transfer capability utilizing both linear and nonlinear power flow analysis methods is developed that acknowledges both thermal and voltage system limitations. The available transfer capability is the incremental transfer capability derived by the method reduced by margins. A procedure for quantifying the first order effect of network uncertainties such as load forecast error and simultaneous transfers on the calculated transfer capability of a power system snapshot are explored. The quantification of these network uncertainties can provide information necessary for system operation, planning and energy market participation.

162 citations


Journal ArticleDOI
TL;DR: In this article, the quality factor of a magnetically-actuated mechanical resonator is controlled by an external electrical circuit, driven by local variation of the electrical impedance presented to the resonator at its resonance frequency.
Abstract: We demonstrate a technique by which the quality factor of a magnetically-actuated mechanical resonator is controlled by an external electrical circuit. Modulation of this parameter is achieved by local variation of the electrical impedance presented to the resonator at its resonance frequency. We describe a theory that explains this result as arising from eddy currents in the external electrical circuit, which are driven by electromotive forces generated through motion of the resonator in the applied magnetic field. The theory is in good agreement with the induced variation in quality factor that we observe.

152 citations


Journal ArticleDOI
TL;DR: In this article, a new method to analyze the performance of grounding systems is presented based on electric circuit theory and is solved by applying a conventional nodal analysis technique, where the problem is treated in the frequency domain, a transient response may be obtained by means of the Fourier transform.
Abstract: A new method to analyze the performance of grounding systems is presented. The model is based on electric circuit theory and is solved by applying a conventional nodal analysis technique. Although the problem is treated in the frequency domain, a transient response may be obtained by means of the Fourier transform. Comparison with other methods and practical applications are presented.

146 citations


Journal ArticleDOI
TL;DR: In this article, the load flow equations are written in terms of new variables resulting in a set of 3N equations (2N linear plus N quadratic) for a network with N+1 buses.
Abstract: This paper presents a method to solve the power flow problem in radial distribution networks. In the proposed formulation, the load flow equations are written in terms of new variables resulting in a set of 3N equations (2N linear plus N quadratic) for a network with N+1 buses. A computationally efficient solution scheme based on the Newton-Raphson method is proposed, and possible simplifications are discussed. Finally, a comparative evaluation of the proposed method's performance against existing algorithms is provided.

140 citations


Proceedings ArticleDOI
J.H. Alimeling1, W.P. Hammer1
27 Jul 1999
TL;DR: In this article, a toolbox, called PLECS, for the fast simulation of power electronic circuits under Simulink is presented, based on a state-space formulation for circuits that consist of linear elements (RLC), transformers, sources, meters and ideal switches.
Abstract: In this paper a new toolbox, PLECS, for the fast simulation of power electronic circuits under Simulink is presented. This toolbox provides the means for modeling large power electronic systems containing both electrical circuits and controllers. The program is based on a state-space formulation for circuits that consist of linear elements (RLC), transformers, sources, meters and ideal switches. Diodes, thyristors, IGBTs and other nonlinear elements such as saturable inductors can be assembled by combining linear elements and switches. Thus, a piece-wise linear model is attained which leads to a stable and fast simulation. An attached benchmark simulation demonstrates the capability of PLECS.

139 citations


Patent
26 Feb 1999
TL;DR: In this paper, a wall mounted cover plate (40) conceals an electrical circuit (50) capable of sensing the field provided by a covered switch (30) or electrical socket circuit.
Abstract: A wall mounted cover plate (40) conceals an electrical circuit (50) capable of sensing the field provided by a covered switch (30) or electrical socket circuit. When power is lost at the wall circuit the electrical circuit (50) senses the loss of power and activates one or more LEDs (90A) to provide emergency illumination. The electrical circuit (50) is self contained and does not require stand-by energy so that the batteries (58) are long lasting.

127 citations


Patent
14 Jun 1999
TL;DR: An electrical trailer plug device for connecting a trailer electrical system to a tow vehicle electrical system is described in this paper, which includes a first electrical connector configured to connect an electrical current path of the vehicle electrical systems to an electrical circuit supplying electricity from the vehicle Electrical System to one or more trailer lamps supported on the trailer.
Abstract: An electrical trailer plug device for connecting a trailer electrical system to a tow vehicle electrical system. The trailer plug device includes a first electrical connector configured to connect an electrical current path of the vehicle electrical system to an electrical current path of the trailer electrical system to complete an electrical circuit supplying electricity from the vehicle electrical system to one or more trailer lamps supported on the trailer. The device also includes a current protection device configured to limit current in the circuit when current flow in the circuit exceeds a predetermined value. A first sensor light is connected in the circuit with a combination of circuit elements configured to illuminate the first sensor light when current is flowing in the circuit but has not exceeded the predetermined. A second sensor light may be connected in the circuit with a combination of circuit elements configured to illuminate the second sensor light when the current protection device is limiting current flow in the circuit.

112 citations


DOI
01 Jan 1999
TL;DR: In this article, a solution concept for linear complementarity systems is defined by combining a hybrid point-of-view and a distributional framework, and the solution trajectories are defined by a hybrid approach.
Abstract: Technological innovation pushes towards the consideration of dynamical systems of a mixed continuous and discrete nature, which are called “hybrid systems” Hybrid systems arise, for instance, from the combination of an analog continuous-time process and a digital time-asynchronous controller Many consumer products (cars, micro-wave units, washing machines and so on) are controlled by digital embedded software, rendering the overall process a system with mixed dynamics Also many physical systems display hybrid behavior: the description of multi body dynamics depends crucially on the presence or absence of a contact, models of friction phenomena distinguish between slip and stick phases and electrical circuits contain switching elements like diodes that can be blocking (open circuit) or conducting (short circuit) From these examples it is obvious that a too general study of hybrid systems will lack decisive power: it will not result in detailed information on individual elements in the studied class Therefore, one has to consider a subclass of hybrid systems carrying a clear additional structure allowing analysis of its behavior (eg well-posedness, simulation methods, stability) and facilitating systematic controller synthesis However, the chosen subclass must also contain many interesting examples from an application point of view The class of (linear) complementarity systems satisfies both requirements and is the subject of the thesis Complementarity systems are described by differential equations, inequalities and logic expressions and form dynamical extensions of the linear complementarity problem (LCP) of mathematical programming The study of the complementarity class is motivated by a broad range of physically interesting systems that can be reformulated in terms of the complementarity formalism Examples include mechanical systems subject to unilateral constraints, Coulomb friction or one-sided springs; electrical networks with diodes; control systems with saturation or deadzones; piecewise linear and variable structure systems; relay systems; hydraulic processes with one-way valves; and sets of equations resulting from optimal control problems with state or control constraints Moreover, in Chapter 6 it is shown that the class of “projected dynamical systems” also fits into the complementarity framework To obtain a well-founded theory, it is essential to define a physically relevant solution concept and answer the classical questions of existence and uniqueness of solutions Because of the “jump-phenomena” in the system variables and the multimodal behavior, formulating a solution concept for linear complementarity systems (LCS) is non-trivial The solution trajectories are defined by combining a hybrid point of view and a distributional framework After the formal introduction of the solution concept, connections are established with the existing literature on mechanical systems and electrical circuits It is shown that the proposed solution concept is not an artificial one, but that it is in accordance with well-known rules specified for subclasses of complementarity systems

100 citations


Journal ArticleDOI
TL;DR: In this article, the frequency and duration indices of a composite power system are computed using random Monte Carlo sampling selectively on those parts of the state space where failure states are more likely to occur.
Abstract: This paper introduces a method for computing the frequency and duration indices of a composite power system, using random Monte Carlo sampling selectively on those parts of the state space where failure states are more likely to occur. The implementation uses a DC flow model to represent network power flows. The method is tested using a modified form of the IEEE Reliability Test System and is shown to be significantly faster than conventional Monte Carlo simulation, while retaining the same level of accuracy.

Patent
19 Mar 1999
TL;DR: In this article, an apparatus for a method of inhibiting and overriding the normal operating mode of one or more input devices connected to a communications network is presented. But it is not shown how to determine whether a group of input devices is capable of commanding an electrical control device to apply and remove electrical power from an electrical load connected thereto.
Abstract: An apparatus for a method of inhibiting and overriding the normal operating mode of one or more input devices connected to a communications network (14). The present invention functions within an electrical network made up of a plurality of input devices wherein a group of input devices is capable of commanding an electrical control device (18) to apply and remove electrical power from an electrical load connected thereto. The input devices or nodes communicate with the electrical control device over a communications network. When one of the input devices is turned off, the normal operating mode of all the other input sensors (16) are inhibited. The electrical control device remains inhibited until the input devices are no longer in the off position. Thus, electrical power to the load (22) controlled by the electrical control device remains disconnected until all input devices are in the on position. Local and remote signaling, control and indication diagnostic and monitoring functions are also provided.

Journal ArticleDOI
TL;DR: This paper study the quasistatic network/load models for use in steady-state and dynamic power-system analyses and present a set of sufficient conditions which ensures that the network/ load model is solvable for voltages and currents.
Abstract: Virtually all power-system analysis algorithms require the solution of a network/load model. During a numerical simulation of medium and long term dynamic events, this model is solved at every timestep. In all cases it is important that there exists a solution to the model. In this paper we study the quasistatic network/load models for use in steady-state and dynamic power-system analyses and present a set of sufficient conditions which ensures that the network/load model is solvable for voltages and currents.

Patent
20 Jan 1999
TL;DR: In this article, a power converter suitable for use in lighting dimmer control is described, and a number of aspects of the power converter are disclosed, such as the problem of freewheeling, the linearity of the circuit transfer characteristic, and the amplitude of a spike.
Abstract: The present invention relates to apparatus used in power control, such as apparatus for controlling the power level in an AC electrical circuit. Such an apparatus is referred to as an AC power converter. In one form, the present invention particularly relates to a power converter suitable for use in lighting dimmer control although other applications of the present invention are not to be excluded from the scope of the present application. A number of aspects of the power converter are disclosed. One aspect is directed to the problem of freewheeling in a power converter. In another aspect the linearity of the circuit transfer characteristic is improved when operating in response to small load outputs. A further aspect relates to surge detection by controlling the pulse width and accordingly, the amplitude of a spike. In a still further aspect, communication between a number of power converters uses a network such as ethernet, or preferably LONTM.

Journal ArticleDOI
01 May 1999
TL;DR: In this paper, the Whitney-elements time-domain (WETD) method is applied to solve a coupled problem of EM fields and circuits, which are characterized by lumped elements, distributed elements and independent sources.
Abstract: The Whitney-elements time-domain (WETD) method is a very powerful full-wave EM field solver in the time domain The WETD method is here applied to solve a coupled problem of EM fields and circuits, which are characterized by lumped elements, distributed elements and independent sources The method consists in the variation of the finite element functional to include circuit elements in the computational domain By locating the terminals of the lumped elements in two nodes delimiting an edge of the FEM mesh, a simple computational procedure is obtained The distributed elements are modeled as a series of lumped elements The proposed full-wave method is a suitable tool to analyze electrical circuits and EM fields in complex configurations

Journal ArticleDOI
TL;DR: In this article, a new and efficient simulation model for optimal expansion planning of distribution systems using separable linear programming (LP) technique is presented, which can be used to determine optimum substation sites and transformer sizes, optimum expansion of existing substation, optimal load transfer between substations and load centers, optimal routes and optimum feeder size at each selected route.

Journal ArticleDOI
TL;DR: In this article, a new approach using fuzzy set theory for reactive power control with the purpose of improving the voltage stability of a power system is presented, where voltage stability index and controlling variables are translated into fuzzy set notations to formulate the relation between voltage stability level and controlling ability of controlling devices.

Patent
15 Sep 1999
TL;DR: In this paper, a response form containing a means of input that on manual influence can switch a conducting electrical circuit connected to an electronic unit is incorporated into the response form for registration of the said influence.
Abstract: A response form containing a means of input that on manual influence can switch a conducting electrical circuit connected to an electronic unit (40) incorporated into the response form for registration of the said influence. The present invention provides such a response form at low cost and enables the use of the response form as a patient journal. The patient journal also can be integrated with a pharmaceutical response package. The response package is formed of a disposable material in the form of a sheet (12), and a conducting circuit (26) is printed onto one side (16) of the disposable material. The means of input can consist of circuit makers (30, 32) that are visually marked-on one side of the disposable material and that are arranged to make electrical contact across an interrupted loop (28) of the conducting circuit (26) upon pressing together localized inner surfaces (14, 16) of the disposable material which face each other. The means of input also may consist of circuit breakers that are visually marked on pieces of the disposable material and arranged to cause electrical interruption in a loop of the conducting circuit when these pieces are at least partially removed from the response form.

Patent
21 Dec 1999
TL;DR: In this article, a system for determining whether arcing is present in an electrical circuit includes a sensor for monitoring a current waveform in the electrical circuit, and an arc fault detection circuit which determines whether an arcing fault is present.
Abstract: A system for determining whether arcing is present in an electrical circuit includes a sensor for monitoring a current waveform in the electrical circuit, and an arc fault detection circuit which determines whether an arc fault is present in response to the sensor. The arc fault detection circuit includes a controller which produces a trip signal in response to a determination that an arcing fault is present in the electrical circuit, and an inhibit/blocking function for preventing the production of the trip signal under one or more predetermined conditions.

Journal ArticleDOI
TL;DR: In this paper, the performance of an Elman recurrent network-based relay to determine the fault direction on a transmission line on fault data recorded in the field is described, which uses samples of voltage and current signals to learn the hidden relationship existing in the input patterns.
Abstract: Summary form only given as follows. Performance of an Elman recurrent network-based relay to determine the fault direction on a transmission line on fault data recorded in the field is described in this paper. The network uses samples of voltage and current signals to learn the hidden relationship existing in the input patterns. Studies show that the proposed network is able to identify the fault direction correctly and rapidly. Results obtained indicate that the proposed network is robust, fast and accurate.

Patent
02 Sep 1999
TL;DR: In this paper, an apparatus for monitoring the operation of electrical circuits on a vehicle trailer is described. But this apparatus is not suitable for towing vehicles, as it is unsuitable for the use in towing a vehicle.
Abstract: The invention concerns an apparatus for monitoring the operation of electrical circuits on a vehicle trailer 10, and has a monitoring unit 18 including a monitor circuit 32 for outputting a signal in response to failure of a component such as a lamp 12 a -12 d of a trailer electrical circuit. The monitoring unit also has a transmitter 34 for passing a failure indication signal to a receiver 90 of an indicator unit 26 which is mounted in a towing vehicle 14 in a position where it can give an indication of failure of the component to the vehicle driver.

Patent
11 Aug 1999
TL;DR: In this paper, a docking station is used to charge a portable electrical energy source to a vehicle having a DC power supply and charge a battery contained in the portable energy source. But it is not shown how to attach the platform to a structure of the vehicle.
Abstract: A docking station secures a portable electrical energy source to a vehicle having a DC power supply and charges a battery contained in the portable electrical energy source. The docking station includes a platform adaptive for receiving the portable electrical energy source. A first attaching mechanism removably fixes the portable electrical energy source to the platform. A second attaching mechanism fixes the platform to a structure of the vehicle. An electrical circuit has an input adapted for connection to the DC power supply of the vehicle and an output adapted for connection to the battery of the portable electrical energy source while the portable electrical energy source is fixed to the platform. A circuit is coupled between the input and output of the electrical circuit for controlling charging of the battery of the portable electrical energy source.

Patent
22 Apr 1999
TL;DR: In this paper, an efficient method for automatically verifying test patterns devised to detect speed critical faults in electrical circuits, with minimal human intervention, is presented, which provides a controlled momentary inversion of a logic value at a control point within the circuit being tested or simulated, and then checks the measured or simulated circuit's output value.
Abstract: An efficient method is presented for automatically verifying test patterns devised to detect speed critical faults in electrical circuits, with minimal human intervention. The method provides a controlled momentary inversion of a logic value at a control point within the circuit being tested or simulated, and then checks the measured or simulated circuit's output value. If the momentary logic inversion causes an inverted logic output, then the test pattern under evaluation has been determined to be capable of detecting circuits that have failures due to speed critical problems. With such an arrangement it is possible to determine whether specific test patterns will accurately measure the performance of circuit paths that have potential operating speed related problems.

Patent
27 May 1999
TL;DR: In this paper, the authors used mid-infrared high-power pulsed laser radiation sources for drilling high-quality microvia interconnection holes in printed circuit (wiring) boards and other electrical circuit packages.
Abstract: This invention relates to using mid-infrared high-power pulsed laser radiation sources for drilling high-quality microvia interconnection holes in printed circuit (wiring) boards and other electrical circuit packages.

Journal Article
TL;DR: The need to model complex electrical components by developing abstract representations for the behaviour to supplement the qualitative electrical simulation is addressed by addressing the need to build qualitative models for complex components.
Abstract: Automotive electrical and electronic systems have become very sophisticated in a relatively short time. This complexity has both led to the increased need for design analysis tools and the need for these tools to deal with more complex components. Qualitative simulation of electrical circuits has proven to be invaluable in the development of several design analysis techniques and the ability to build qualitative models for complex components has become essential to allow effective use of these tools.We have addressed the need to model complex electrical components by developing abstract representations for the behaviour to supplement the qualitative electrical simulation. This development has been carried out in two stages. In the first stage we provide the ability to include dependencies between the electrical activity in one part of a component and the (qualitative) resistance values in another. This approach is known as QCAT (Qualitative Circuit Analysis Tool), an early version of which is documented in {PughSnooke96} and has been implemented in the industrially used FMEA tool, Autosteve. The second stage (QCATdSB) uses state based descriptions to allow more complex behaviour descriptions including temporal specifications. QCATdSB will be included in the next release of Autosteve.

Book ChapterDOI
TL;DR: In this article, a new class of weakly positive singular continuous-time systems has been introduced, and necessary and sufficient conditions have been established (Theorem 2) under which a weak positive singular system (1) can be reduced by the strict equivalence transformation (10), (12) to the positive standard system (15), (15).
Abstract: A new class of weakly positive singular continuous-time systems has been introduced. It has been shown that the equations (1a) and (7) have the same solution (8). Necessary and sufficient conditions have been established (Theorem 2) under which a weakly positive singular system (1) can be reduced by the strict equivalence transformation (10), (12) to the positive standard system (15), (15). It has been shown that linear electrical circuits consisting of resistances, inductances (capacitances) and source voltages are examples of positive singular continuous-time linear systems and they can be reduced to positive standard systems.

Journal ArticleDOI
TL;DR: In this article, a time domain model for the representation of powers in linear and nonlinear electrical circuits is presented, which can account, in a physical or engineering sense, for "active and reactive powers" as functions of time.
Abstract: Summary form only given as follows. This paper presents a time domain model for the representation of powers in linear and nonlinear electrical circuits. The model can account, in a physical (or engineering) sense, for "active and reactive powers" as functions of time. The model is based on the time domain decomposition of the instantaneous power p(t) into two components: p(t)=a(t)+r(t). Where, a(t) represents the instantaneous power consumed by the (linear or nonlinear) load. The information regarding the store/restore process is contained in r(t). In contrast with the traditional frequency domain model in which powers are defined orthogonal (i.e. S/sup 2/=P/sup 2/+Q/sup 2/+D/sup 2/+...) and therefore they do not interact with each other, the proposed model permits the interaction of active and reactive powers at every instant. Using the model of the paper we can obtain the instantaneous power needed for compensation of both wave shape and power factor.

Book
01 Aug 1999
TL;DR: A holistic approach to the automatic creation of a circuit's topology, sizing, placement, and routing is described, illustrated with the problem of designing an analog lowpass filter circuit.
Abstract: The design of an electrical circuit entails creation of the circuit's topology, sizing, placement, and routing. Each of these tasks is either vexatious or computationally intractable. Design engineers typically perform these tasks sequentially– thus forcing the engineer to grapple with one vexatious or intractable problem after another. This chapter describes a holistic approach to the automatic creation of a circuit's topology, sizing, placement, and routing. This approach starts with a highlevel statement of the requirements for the desired circuit and uses genetic programming to automatically and simultaneously create the circuit's topology, sizing, placement, and routing. The approach is illustrated with the problem of designing an analog lowpass filter circuit. The fitness measure for a candidate circuit considers the area of the fully laid-out circuit as well as whether the circuit passes or suppresses the appropriate frequencies. Genetic programming requires only about 1 1/2 orders of magnitude more computer time to create the circuit's topology, sizing, placement, and routing than to create the topology and sizing for this illustrative problem.

Journal ArticleDOI
TL;DR: The paper presents a new approach for the measurement of power system harmonic components and is based on fuzzy linear regression, where the coefficients of this function are assumed to be fuzzy numbers having a certain middle and spread value.

Journal ArticleDOI
TL;DR: An automatic method to produce compact equivalent circuit models of spatially inhomogeneous resistors using the public domain circuit simulator SPICE3 for the example of a magnetic Hall sensor, with and without the piezoresistive effect.
Abstract: We present an automatic method to produce compact equivalent circuit models of spatially inhomogeneous resistors. Local variations in space of the resistivity due to physical interactions such as magnetic fields or mechanical stress are automatically included. The equivalent circuit model is computed using symbolic algebra, such that the functional relation between the resistivity and the fields interacting with it is included in the circuit design model. Modeling is based on the discretization of the sensor geometry with a mesh of elements and vertex nodes together with the current continuity equation using the box integration method. The resistivity is described by the tensor field of electrical conductivity and depends on the physical interactions to be modeled. The element internode conductivity is mapped to a set of lumped conductances and transconductances (voltage controlled current sources) between the nodes of the discretization mesh. These conductances and transconductances are translated into an equivalent circuit net list. Optionally, the electrical network representing the sensor is simplified before translation by symbolic linear algebra. Thus, equivalent circuit models consisting of many simple elements can be generated as well as models with only a few, algebraically complicated elements. The method is demonstrated using the public domain circuit simulator SPICE3 for the example of a magnetic Hall sensor, with and without the piezoresistive effect.