Showing papers on "Electrical network published in 2001"

Topologies for VSC transmission

Abstract: The increasing rating and improved performance of self-commutated semiconductor devices have made DC power transmission based on voltage-source power convertors (VSCs) possible. This technology is called VSC transmission. The main components in a DC scheme are depicted and their functions explained. The features of three main categories of convertor topology suitable for DC transmission are described. Three specific convertors viz. two-level, three-level diode-clamped and four-level floating-capacitor convertors for a 300 MW scheme are compared in terms of costs, DC capacitor volume, commutation inductance and footprint. The floating capacitor convertor is shown to yield the lowest system cost.

Transients in Power Systems

Abstract: Covering the fundamentals of electrical transients, this book should equip readers with the skills to recognise and solve transient problems in power networks and components. Starting with the basics of transient electrical circuit theory, and moving on to discuss the effects of power transience in all types of power equipment, it provides insight into this important field. Recent advances in measurement techniques, computer modelling and switchgear development are given comprehensive coverage for the first time. An electromagnetic transients calculation program is included and should prove valuable to both students and engineers in the field.

Intrabody communication for a hearing aid

Abstract: A hearing aid system (20) includes one or more acoustic I/O components (30a, 30b) operable to receive an acoustic input and a processing component (30c). These components (30a, 30b, and 30c) are electrically coupled together by a closed electrical circuit including at least one electrical conduction pathway formed by skin of a user. An electrical signal is transmitted between the components (30a, 30b, 30c) with the closed electrical circuit. Communication between the components (30a, 30b, 30c) can be one-way or two-way.

Battery clamp with integrated current sensor

Abstract: An apparatus configured to couple to a battery contact is provided. The apparatus includes an electrical connector for connection to a battery contact and a current sensor coupled to the electrical connector, the current sensor is used for measuring current through an electrical conductor. In addition, a method of coupling an electrical circuit to a battery contact is provided.

Compact non-contact electrical switch

Abstract: A compact non-contact electrical switch for use in an electrical box mounted on a wall has a capacitance sensor for detecting a presence of a hand placed adjacent to the switch and for generating a first data bit, and a CPU for receiving the data bit and for calculating a power output in response to the first data bit. The CPU generates a control signal for controlling a triac or relay and thus the power supplied to an electrical circuit passing through the box, for on/off and optionally dimmer control responsive to the proximity of the hand.

Direct current electrical system arc detection apparatus and method

Abstract: Disclosed is an arc detection circuit for monitoring an electrical distribution system which results in detecting arcing in the electrical distribution system and the ability to provide notification and protection for such arcing. The system functions to monitor the electrical distribution system to sense the frequencies of signals in the system using appropriate filtering. One type of filtering which may be used is based upon a heterodyning circuit which provides variable frequency filtering for filtering a signal representative of the current in at least one electrical circuit of the electrical system. The heterodyning circuit output is configured to produce a signal which may be logarithmically related to the filtered signal. If the output signal exceeds a predetermined limit (representative of noise) for a predetermined period (representative of a typical arc duration), the system generates an arc signal. The arc signal may then be used to operate a circuit interrupter or an indicator in a circuit protection system.

Safety devices for electrical circuits and systems

Abstract: A protective device for minimizing fire danger in the use of electrical circuits comprises a unit having a mechanically biased conductive element in series with the circuit, and maintained in position under tension by a fusible material such as a Cerro alloy having a yield point at a selected temperature threshold. When overheating at some other point in the circuit results in a rise of temperature at the protective device, the yielding of the fusible material allows the conductive element to spring free, opening the circuit and cutting off the current. This arrangement is useful in an male plug integral to or separate from an extension cord or power cord, in conjunction with circuit breaker systems, in a in-circuit device, and in electrical appliances and devices.

Motivational apparatus for controlling use of electronic devices and method of use

Abstract: A motivational apparatus for controlling use of an electronic device, wherein the apparatus is interconnected between a source of transmission (e.g. power) and the electronic device to control transfer of transmissions from the transmission source to the electronic device. The apparatus comprises a plurality of electrical switches, a master switch, and a plurality of light-emitting diodes. A list of tasks is prepared and associated with the electrical switches such that one task corresponds to one electrical switch. As each task is completed, the electrical switch corresponding to that task is actuated to light up the diode corresponding to that switch. After all of the tasks are completed, a parent or supervisor may confirm satisfactory completion of the tasks and then actuate the master switch to close the electrical circuit, thereby allowing transfer of transmissions from the transmission source to the electronic device such that the electronic device is operational.

Active filters for power quality improvement

Abstract: This paper deals with problems related with harmonics in power system networks. Several international standards issued to control power quality problems are briefly described and some important methods to analyse electrical circuits with non-sinusoidal waveforms are introduced and evaluated. One of these methods - the p-q theory - was used to implement the control algorithm of a shunt active filter, which is also described in this paper as an application example. The filter can compensate for harmonic currents, power factor and load unbalance. Both simulation and experimental results are presented, showing that good dynamic and steady-state response can be achieved with this approach.

On the Solution of Parametrised Linear Systems

Abstract: Considered are parametrised linear systems which parameters are subject to tolerances Rump’s fixed-point iteration method for finding outer and inner approximations of the hull of the solution set is studied and applied to an electrical circuit problem Interval Gauss-Seidel iteration for parametrised linear systems is introduced and used for improving the enclosures, obtained by the fixed-point method, whenever they are not good enough Generalised interval arithmetic (on proper and improper intervals) is considered as a computational tool for efficient handling of proper interval problems (to obtain inner interval estimations without inward rounding and to eliminate the dependency problem in parametrised Gauss-Seidel iteration) Numerical results from the application of the above methods to an electrical circuit problem are discussed

Electrical fault detection circuit with dual-mode power supply

Abstract: An arcing fault protection assembly and a corresponding method determine whether arcing is present in electrical circuits. The assembly powers-up quickly without dissipating excessive heat while power is being supplied to the assembly. The assembly comprises a sensor, a broadband noise circuit, a controller, and a dual-mode power supply. The sensor detects a current flowing in an electrical circuit and develops a corresponding sensor signal. The broadband noise circuit determines the presence of broadband noise in the sensor signal and produces a corresponding output signal. The controller processes the sensor signal and the output signal in a predetermined fashion to determine whether an arcing fault is present in the circuit. The dual-mode power supply supplies power to the sensor, broadband noise circuit and controller using a first mode and later switching to a second mode. The first mode reaches steady state faster than the second mode.

Electrical power system performance simulation

Abstract: A computer program product for simulating the performance of an electrical power system. The computer program product consists of a computer-readable medium containing an electrical power system model module, an input module and a simulation engine. The electrical power system model module contains one or more electrical power system models consisting of interrelated blocks and connections. The blocks represent elements comprising electrical circuits, electromechanical devices, and measurement devices, and the relationships between said blocks and said connections in said model are read-only with respect to an end user. The input module is operable on a computer to allow an end user to specify at least one characteristic for at least one said block in said model. The simulation engine is operable on a computer to simulate the performance of an electrical power system represented by the model using the specified block characteristics.

Piezoelectric generator for sensors inside vehicle tyres

Abstract: A system for generating electrical energy in a vehicle tyre (1) comprises at least one piezoelectric element (9, 109) associated to the tyre (1) which generates electrical energy whenever it is deformed, and this piezoelectric element (9, 109) is elongate, extends along at least a portion of the tyre (1) and is connected electrically to an electrical circuit that is applied to the said tyre (1) and is not in electrical communication with the vehicle. The piezoelectric element (9, 109) preferably comprises a coaxial cable (10) extending along a straight or undulated path of the tyre circumference.

Modeling behavior of an electrical circuit

Abstract: Behavior of an electrical circuit can be modeled using a trained neural network. For example, using one or more neural networks, power consumption, including leakage power and switching energy, can be estimated. Also, a profile of current versus time can be generated for the electrical circuit. A hierarchy of neural networks may be used to model the circuit at different levels. In one embodiment, a circuit behavior is modeled using one or more neural networks, cluster values, and cluster probabilities.

Electrical wire identification markers

Abstract: An electrical wire marker, marking method and system for identifying a wire associated with a particular circuit or to be installed in a particular electrical circuit are disclosed. The wire marker includes an identifier and color indicia. The identifier is associated with a particular electrical circuit in which the wire is to be connected. The color indicia corresponds to a particular color or wire color associated with that particular electrical circuit.

Fuel level sensor

Abstract: A fuel level sensor for use with a vehicle fuel tank includes a magnet carrying float assembly that rises and falls with the fuel level to open and close various magnetically activated reed-switches located at different axial positions along a vertically extending electrical circuit. Activating a reed-switch located at a particular vertical position along the electrical circuit causes the overall resistance of the circuit to depend upon the position of the float assembly. The float assembly is capable of freely rotating about the vertical axis of the electrical circuit and carries magnets producing a horizontal magnetic field that can activate a reed-switch from any angular orientation of the float assembly. Thus, assuming the fuel level sensor is provided with a constant voltage source, the sensor is able to determine the fuel level by the amount of electrical current flowing through the circuit. The electrical current outputted from the sensor is sent to a fuel level gauge which translates the electrical signal into a visual reading, thereby informing an operator of the current fuel level.

Electrical interrupt switch

Abstract: An electrical circuit interrupter for a conventional electrical plug is provided that be mounted on a wall electrical socket or on the plug itself. Adaptable to either 2-prong or 3-prong electrical plugs, a toggle switch either turns on or off the circuit from the plug to the wall socket.

3-D modeling of thin wire and thin plate using finite element method and electrical circuit equation

Abstract: This paper presents a method of modeling an electric circuit of thin wire and thin plate submitted to an electromagnetic field. The proposed method requires a preliminary electrokinetic computation to find the current distribution on the plate due to a unit current and the magnetic field distribution. To compute the final current in the system, we model the thin plate as an electrical circuit component.

Battery operable device with battery state-of-charge indicator

Abstract: A battery operable electrical device, such as a mobile telephone or a laptop computer, with a clock frequency generator operable to generate electrical clock frequency signals, and a first electrical circuit adapted to perform a first or main function of the device, utilising the clock frequency signals generated by the clock generator. The device further includes a second electrical or auxiliary circuit adapted to generate an electrical excitation signal with an excitation frequency derived from the clock frequency signals. the excitation signal is fed to battery terminals of the device, and the second electrical circuit receives, from a battery connected to the battery terminals, an electrical signal in response to the excitation signal, and to analyse the received signal for the battery impedance at the excitation frequency and, based on the battery impedance, the state-of-charge of the batterz is estimated.

Permanent-magnet linear actuator for static and reciprocating short-stroke electromechanical systems

Abstract: With the rapid progress in permanent-magnet technology, through the use of high-energy-density rare-earth materials a range of compact and high-performance linear actuators is now available. The paper presents simulated and experimental results from an investigation into the performance of such a device, in which the internal operating conditions are first modeled using a finite-element approach. Information obtained from this investigation is used, together with equations for both the electrical circuit and the mechanical motion, to enable both the static and the dynamic characteristics to be predicted. The most significant parameters affecting the performance of the actuator are identified, and an optimized design is produced.

Network analyses of ventilation system for large hydrogenerator

Abstract: In this paper, ventilation systems of a large hydro-generator are analyzed. A new method named network analyses is presented to calculate ventilation circuits. The general equations are obtained by the electrical network theory. The equations are solved numerically with the successive iterative method. A general program of FORTRAN language is worked out. The ventilation system of the hydrogenerator in Sanxia power station is calculated with the network analyses method.

Insulation monitoring method for unearthed electrical network uses pulses AC voltage applied between network and earth and evaluation of measured current values

Abstract: The insulation monitoring method has a pulsed AC voltage connected between the unearthed network (1) and earth, with calculation of the ohmic insulation resistance from the difference between successive measured values for the measuring current. A time constant for the network is determined for each pulse voltage value, with measurement of the measuring current at a multiple of the time constant and comparison with a control value for detection of measuring errors. An Independent claim for an insulation monitoring device for an unearthed electrical network is also included.

Modular back-to-back HVDC, with Capacitor Commutated Converters (CCC)

Abstract: 1. SUMMARY A back-to-back HVDC arrangement is used when two asynchronous AC systems need to be interconnected for bulk power transmission or for AC system stabilization reasons. In an HVDC back-to-back station there are no overhead lines or cables separating the rectifier and the inverter, hence the transmission electrical losses on the DC side can be neglected. In a back-to-back HVDC, the DC current can be kept high and the DC voltage low. The low DC voltage means that the air clearance requirement is low, which is in favor of a compact design of the valve housings. This enabled the modular back-to-back HVDC concept to be developed. The modular back-to-back converter station can be made very compact, thus requiring a minimum of open space. It can even be designed to fit into an existing right-of-way of a typical 400 kV AC line. In environmentally sensitive areas this is also considered a great advantage from a permitting point of view. Our ISO 14001 certification states that the design of the equipment and the construction at the site are performed in an environmentally acceptable way. The Argentinean and Brazilian networks have been interconnected via back-to-back HVDC with a rating of 1100 MW. A second interconnection of another 1100 MW is under construction. The back-to-back HVDC converter stations are of the modular type with capacitor commutated converters.

A PDAE Model for Interconnected Linear RLC Networks

Abstract: In electrical circuit simulation, a refined generalized network approach is used to describe secondary and parasitic effects of interconnected networks. Restricting our investigations to linear RLC circuits, this ansatz yields linear initial-boundary value problems of mixed partial-differential and differential-algebraic equations, so-called PDAE systems. If the network fulfils some topological conditions, this system is well-posed and has perturbation index 1 only: the solution of a slightly perturbed system does not depend on derivatives of the perturbations. As method-of-lines applications are often used to embed PDAE models into time-domain network analysis packages, it is reasonable to demand that the analytical properties of the approximate DAE system obtained after semidiscretization are consistent with the original PDAE system. Especially, both should show the same sensitivity with respect to initial and boundary data. We will learn, however, that semidiscretization may act like a deregularization...

Apparatus and method for electrical testing of electrical circuits

Abstract: Apparatus for electrical testing of electrical circuits includes an array of probes arranged for selective engagement with portions of electrical circuits to be tested, testing circuitry associated with the array of probes for sensing electrical characteristics of the electrical circuits engaged by the array of probes, and control circuitry associated with the array of probes for causing engagement between selected ones of the array of probes with selected ones of the portions of electrical circuits to be tested. The array of probes includes at least two static probe assemblies arranged in a fixed array, and the static probe assemblies include a selectively positionable probe element and a probe element positioner. The apparatus is employed to test electrical circuits during fabrication.

Reactive power control of a wind farm through different control algorithms

Abstract: Electrical systems endowed with variable generating units will dominate the electrical landscape in the near future. These types of generating units will bring new opportunities to utilities, companies and customers, but they will also bring new problems to electrical companies. As wind power generation is one of the most important renewable energy sources, because its production is environmentally clean, it is important to achieve suitable locations for new wind farms. So, to evaluate their impact on the electrical network it is necessary to develop an accurate wind farm model for the network analysis program. This paper presents the model of a wind farm made up exclusively of double fed induction machines and the control algorithm that has been developed in order to maintain the reactive power set point fixed by the electric company. Consequently, the voltage levels of the network that the wind farm is connected to, would also be controlled.

System and method for determining the required decoupling capacitors for a power distribution system using an improved capacitor model

Abstract: A system and method for determining the required decoupling capacitors for a power distribution system using an improved capacitor model. In one embodiment, a method for determining the decoupling capacitors for a power distribution system includes creating a model of the power distribution system using circuit simulation software, such as SPICE. The power distribution system model includes a plurality of cells interconnected at predetermined nodes. The method then selects one or more decoupling capacitors for the power distribution system. The decoupling capacitors are represented in the power distribution system model by a capacitor model, which is a mathematical model of an electrical circuit. The electrical circuit upon which the capacitor model is based is a ladder circuit. Following the selecting of the decoupling capacitors, the power distribution system model is update based on the selections, and operation of the power distribution system is then simulated. During the simulation, transfer impedance values are determined for each of the nodes, and compared to target impedance. The method is then repeated until each of the transfer impedance values is at or below the target impedance.

Sensor controlled water heater and method of use

Abstract: A water heater apparatus for aircraft applications has three water heating tubes joined in series interconnection and positioned in side-by-side adjacency, where each of the tubes provides an electrical resistance heater part of a 3 phase electrical power circuit. Each tube also has a thermostat, and an electrical circuit breaker. The thermostats establish an open electrical circuit if water temperature exceeds a temperature set point. The circuit breakers establish an open circuit if electric current flow exceeds an electrical current set point. The apparatus uses a pressure check valve to expel pressure from the water heating tubes when pressure exceeds a water pressure set point. A temperature sensor is positioned for sensing water temperature at a water outlet and an ultrasonic water flow sensing switch identifies water flow in the water heating tubes.

Method and apparatus for analyzing small signal response and noise in nonlinear circuits

Abstract: The present invention relates generally to analyzing small signal response and noise in nonlinear circuits. One embodiment relates to a computer implemented method for analyzing an electrical circuit. The method includes receiving a circuit description and circuit element models, generating circuit equations using the circuit description and models, and determining a periodic stead-state response of the electrical circuit in the time domain. The method further includes linearizing the circuit element models about the steady-state response, generating a time-varying linear system of equations, and representing a small signal solution to the time-varying linear system of equations in response to a sine wave input as an amplitude modulated sine wave. The method also includes discretizing the time-varying linear system of equations by discretizing only the amplitude modulation of the small signal solution and performing a time-varying small signal analysis of the electrical circuit using the discretized equations.