Showing papers by "Westinghouse Electric published in 1984"

Visual momentum: a concept to improve the cognitive coupling of person and computer

Abstract: Computer display system users must integrate data across successive displays. This problem of across-display processing is analogous to the question of how the visual system combines data across successive glances (fixations). Research from cognitive psychology on the latter question is used in order to formulate guidelines for the display designer. The result is a new principle of person-computer interaction, visual momentum, which captures knowledge about the mechanisms that support the identification of “relevant” data in human perception so that display system design can support an effective distribution of user attention. The negative consequences of low visual momentum on user performance are described, and display design techniques are presented to improve user across-display information extraction.

Solar cell contact resistance—A review

Abstract: An overview of ohmic contacts on solar cells is presented The fundamentals of metal-semiconductor contacts are reviewed, including the Schottky approach, Fermi level pinning by surface states, and the mechanisms of thermionic emission, thermionic/field emission, and tunneling for current transport The concept of contact resistance is developed and contact resistance data for several different contact materials on both silicon and gallium arsenide over a range of doping densities are summarized Finally, the requirements imposed by solar cells on contact resistance are detailed

Contact resistance: Its measurement and relative importance to power loss in a solar cell

Abstract: The concept of contact resistivity is discussed briefly and a technique for its measurement is presented. This technique allows for resistive contact material and for the possibility that the semiconductor sheet resistance beneath the contact differs from the semiconductor sheet resistance beside the contact. The test pattern is unique in that the effects of contact resistance are accumulated over the pattern, nearly unencumbered by voltage and current probes which might otherwise influence the current flow. Measurements of contact resistivities for typical solar cell metallizations using this technique are reported to be in the mid 10-6Ω-cm2range. The relative importance of contact resistance compared to other sources of power loss in a solar cell is determined for a typical contact system. Expressions derived in order to make this comparison are useful for evaluating and optimizing a solar cell contact system. Values of series resistance calculated using these expressions are compared with measured values.

Modification of polymer-gel structures

Abstract: In metal-organic driven systems, gelling occurs as a result of the formation of a polymeric network by simultaneous and competing chemical reactions. The resultant polymeric units consist of an inorganic network, similar to that of oxide glasses, framed by hydroxyl and organic groups. The extent of polymerization as well as the structure of the polymeric network are determined by the hydrolysis and polymerization reactions. By controlling the kinetics of these reactions, it is possible to alter the polymeric structure of the gels. The effect of these molecular-structural variations in the gel is maintained in the glass and ceramic materials derived from the gels, thus allowing property modification of ceramic materials without compositional variations.

Universal process control device and method for developing a process control loop program

Abstract: A distributed processing unit (DPU) or drop which performs process control and data acquisition functions in a distributed processing control system having a data highway linking a plurality of such units. A DPU functional processor accesses the local process I/O interface thereby continually receiving plant information for storage in digital form and subsequent use in the functional processor or for transmission along the data highway. DPU control programs use process values in a transparent fashion, that is without regard to whether these values were obtained through local process I/O interface or via the data highway. The DPU software structure is made up of execution software and support software. The execution software is a collection of data acquisition and process control programs which are developed at an engineer's console drop using a DPU programming language which operates in text and CRT graphic display modes, the latter programming modes allowing system documentation via hard copy graphic display printout. These programs are initiated, performed consecutively, and repeated at specified intervals. The support software initiates process loop execution. Control programs which have been presented to the DPU as representations of ladder diagrams for sequential control or process flow diagrams for continuous process control are executed in the DPU functional processor to achieve the required process control operation.

Optical data distribution network with listen-while-talk capabilities

Abstract: An optical data distribution network including a plurality of drops and apparatus for distributing optical data signals to the plurality of drops wherein each drop has listen-while-talk capability is disclosed. Each drop comprises a single length of optical fiber for propagating transmit and receive optical signals between a directional coupler and the distributing apparatus. The directional coupler is operative to direct the transmit optical signals from an optical transmitter to the single length of optical fiber and to direct the receive optical signals from the single length of optical fiber to a first optical receiver. Each drop further includes a second optical receiver coupled to the directional coupler for receiving optical signals transmitted by the optical transmitter as directed to the second optical receiver by the directional coupler.

Moisture Equilibrium Charts for Transformer Insulation Drying Practice

Abstract: A set of moisture equilibrium charts applicable to transformer insulation is presented. These may be used for the estimation of dryness levels in transformer insulation during the preparative and operational stages, and also during storage. A critique on the well known Piper chart is provided. Techniques to construct equilibrium curves for the combined paper-oil system from indirect measurements are outlined, and the interpretation of these curves for practical situations is discussed.

Wide spectrum antireflective coating for fused silica and other glasses.

Abstract: A method of forming a laser damage resistant wide-spectrum antireflective coating on fused silica and other glasses has been developed. The single-layer graded-index coating is deposited from a specific polymer solution which is converted to a porous SiO2 film. The size of the pores in the film is first reduced by heat treatment to prevent eventual UV scattering. Refractive-index gradation is achieved by grading this non-scattering porosity using a mild etching agent to a depth which is sufficient to smooth the density transition from air to the substrate glass. The resultant coating provides antireflectivity over the entire transmission range of silica extending to wavelengths as short as 250 nm. Laser damage thresholds as high as 9 J/cm2 at 350 nm have been demonstrated for this coating on fused silica substrates, which makes it particularly suitable for the optics of high-power lasers.

Method and apparatus for monitoring transformers

Abstract: A microprocessor-based transformer monitoring system to provide continuous on-line monitoring and analysis of transformer operation. The transformer monitoring system periodically monitors various parameters related to transformer load and condition. Maximum, minimum, and instantaneous values of the parameters are stored and analzyed. To perform the analysis, a hierarchy of thresholds is associated with each parameter. When a parameter exceeds any one of the thresholds, a response is produced by the transformer monitoring system. The type of response depends on the level of the exceeded threshold in the hierarchy. The range of response produced by the transformer monitoring system includes: continuing normal periodic data collection and analysis, increasing the rate of data collection and analysis, recommending an on-site physical check of the monitored transformer, reducing transformer load, and taking the transformer off line.

Power line communications terminal and interface circuit associated therewith

Abstract: A communications terminal for transmitting and receiving communication signals over a power line communications network and including an interface circuit for coupling the terminal to the power line of the network is disclosed. One embodiment of the network includes a transformer for coupling communication signals between the power line and terminal. The coupled communication signals are measured from the secondary of the transformer and used to govern an amplifier circuit which generates matched signals, representative of the measured communication signals. The matched signals are inverted in polarity at the output stage of the amplifier and applied to the secondary winding of the transformer to cancel substantially the electromagnetically coupled communication signals from the power line, thereby providing a high bridging impedance to the power line communication signals without impeding substantially the coupling of the terminal's own communication signals.

Receiver apparatus for three-phase power line carrier communications

Abstract: A transceiver is provided with both voltage and current coupling to a three phase transmission line system. Each phase conductor is coupled to a common point which is connected in signal communication with an input to a receiver. Another input of the receiver is coupled to the neutral conductor of the power line system by an H-field coupler. A signal coupling unit is associated with the voltage couplers between the common connection point and the first receiver input. The receiver is provided with the capability of comparing the voltage signal with the current signal and selecting the stronger of the two. Therefore, the transceiver of the present invention is less adversely affected by standing wave problems since the voltage and current signals are out of phase and voltage nodes are associated with current antinodes and vice versa. Therefore, regardless of the location along the standing wave that the transceiver is located, the best signal available will be used for demodulation purposes.

Wireless power line communication apparatus

Abstract: A field configuration terminal is provided that does not require physical or electrical connection to a remote device of a power line communication system. A toroid is provided that comprises a multiplicity of turns of a conductor that is connected in electrical communication with an amplifier and receiver circuitry within the field configuration terminal. A battery, with associated power supply components, provides a direct current source for the microprocessor and logic of the field configuration terminal and for the amplifier thereof. The toroid of the field configuration terminal is shaped to be disposed around a load management terminal of a power line communication system without physical or electrical contact therewith. Signals are transmitted to and received from the load management terminal by inductively coupling the toroid with the load management terminal in signal communication.

The Vacuum Interrupter Contact

Abstract: A survey of developments in electric contact design for vacuum interrupters is presented. The major emphasis is placed upon those characteristics of contact design that have led to practical vacuum interrupters. A brief description is given of the different modes of vacuum arc that have been observed and how these modes occur during one-half cycle of high current arcing. In the main body of the paper the design philosophy behind vacuum interrupter contact design is presented. It is shown that only two classes of contact have achieved practical utilization. The first of these design classes causes a magnetic field to be impressed at right angles to the arc current and hence, causes the arc to move rapidly over the contact face. The second design class impresses a magnetic field parallel to the arc current. This forces the arc into a diffuse mode with many widely separated cathode spots and a diffuse current collection at the anode even at very high currents. Each of these contact designs is discussed and their advantages and disadvantages are deline- ated.

Spalling and corrosion resistant ceramic coating for land and marine combustion turbines

Abstract: This is an improved process for fabricating a turbine blade for use in land based or marine combustion turbines and in particular is a thin ceramic coating applied to at least the portion of the blades which is designed to operate in the 1100°-1500° F. temperature range and especially in turbines designed to be useable with contaminated fuels. The invention utilizes a 1-4 mil thick ceramic coating on at least a portion of the blade designed to operate in the 1100°-1500° F. temperature range and utilizes a process in which the blade is controlled to a temperature of at least 1200° F. during the application of the ceramic coating.

Method and apparatus for improving the servicing of an elevator system

Abstract: Methods and apparatus for improving the servicing of an elevator system based upon the actual usage of its many functions. The usage of predetermined elevator system functions is monitored and data is collected relative thereto. Threshold and limit parameters are provided for the monitored functions, which parameters are periodically compared with the usage data. The reaching of a usage threshold parameter by a monitored function results in predetermined associated maintenance services being added to a maintenance due list. When a monitored function reaches its associated limit parameter, a need for scheduled elevator preventive maintenance is indicated for all of the maintenance services on the maintenance due list.

Eelectrostatic Charging Tendency of Transformer Oils

Abstract: Three different comnercially avaiTable transformer oils were evaluated for their electrostatic charging behavior. One of these oils was found to have a higher charging tendency than the others. The charging behavior of this oil was moisture dependent; drying of the oil raised the charging level while addition of moisture lowered it. All the oils showed similar temperature dependence on charging behavior in a near exponential manner. Associated with high charging behavior was higher than normal electrical conducti vi ty and lower interfacial tension. The charging tendency is attributed to certain polar compounds in trace quantities, most likely surface active agents. These substances may be present in the refined oil or introduced later in the processing and handling stages.

Low temperature process for annealing shallow implanted n+/p junctions

Abstract: Disclosed is a low temperature technique for annealing implantation damage and activating dopants. Conventional furnace annealing requires temperatures as high as 1000° to 1100° C. to completely anneal the dopant implantation damage; 75 KeV arsenic implantation followed by 550° C. for 75 minutes and 900° C. for 30 minutes in nitrogen for instance is not sufficient to anneal the implantation damage and results in a leakage current of the order of 1 mA per cm 2 . If, however, subsequent to the arsenic implantation, 0.4 KeV hydrogen ions are implanted using a Kaufman ion source with an accelerator current of 200 milliamp, then only 500° to 600° C. for one hour anneal in nitrogen is sufficient to eliminate the arsenic implantation damage. This results in a leakage current of the order of 5 to 25 nA per cm 2 and a complete dopant activation is achieved.

Some results on operator performance in emergency events

Abstract: This paper synthesizes results from several studies of operator performance in simulated power plant emergencies and from retrospective analyses of operator performance in five actual power plant critical incidents. This synthesis is feasible because all of these studies used process tracing techniques and a common perspective on decision making as the basis for their analysis of operator performance. The paper focuses on two areas: operator's ability to detect and correct errors and how operators utilize procedures. The results in these areas are assessed in terms of their implications for concepts and models relevant to operator performance and in terms of their implications for man-machine system improvements.

Comparison Tests of Fourteen Distribution load Forecasting Methods

Abstract: Fourteen methods of forecasting future distribution system loads are tested in a uniform comparison of forecast accuracy, data needs, and resources.Concentration is on comparison of techniques compatible with modern computer and distribution engineering systems Evaluation is based on usefulness as a planning tool, forecast accuracy, and cost of application. Results are generalized as to applicable situations as a function of utility size and growth rate.

Design, fabrication, and analysis of 17-18-percent efficient surface-passivated silicon solar cells

Abstract: A simple analytical model has been developed which provides useful guidelines for fabricating high-efficiency silicon solar cells. Consistent with the model calculations, both surfaces of n+-p-p+solar cells were passivated by a thin layer of thermally grown SiO 2 . Oxide passivation resulted in 17.2-percent efficient solar cells on 4 Ω . cm base material. Passivated cells show about 3 mA/cm2increases in J SC , ∼20 mV improvement in V OC , and ∼2-percent increase in absolute cell efficiency compared to the counterpart 15.2-percent efficient unpassivated cells. The majority of improvement in V OC came from the emitter surface passivation, while both front- and back-surface passivation contributed to the increase in J SC . The emitter region should not be regarded as a "dead layer" because emitter surface passivation can increase the quantum efficiency at short wavelengths from 40 percent to greater than 75 percent.

Protective relay circuit for detecting arcing faults on low-voltage spot networks

Abstract: A protective relay for detecting power arcing faults on a low-voltage spot network. The protective relay can monitor the voltage difference between each phase conductor, the voltage difference between each phase conductor and the neutral conductor, or the current on each phase conductor. Using one of these three sets of values, the protective relay first filters the input signal so that only frequencies indicative of a power arcing fault on the low-voltage spot network are analyzed. The signals passed by the filter are amplified, rectified, and averaged and the peak of each signal detected. If the peak has a duration longer than a predetermined value, a fault indication is provided.

Wind Turbine Generator Interaction With Diesel Generators on an Isolated Power System

Abstract: The Block Island Power Company (BIPCO), on Block Island, Rhode Island, operates an isolated electric power system consisting of diesel generation and an experimental wind turbine. The 150-kW wind turbine, designated MOD-OA by the U. S. Department of Energy is typically operated in parallel with two diesel generators to serve an average winter load of 350 kW. As part of an experimental program to evaluate wind turbine generator performance on the isolated diesel power system, the recordings from an extensive data measurement effort were reviewed and analyzed to define the nature of the dynamic interaction effects. The data were collected over a three-month period on the system to which the DOE/NASA experimental wind turbine was connected. During this time, the diesel units were lightly loaded resulting in up to 60 percent of the total load demand being supplied by the MOD-OA in periods of severely gusting winds. In three of the modes of normal MOD-OA operation. startup???synchronization, shutdown/cutout, and continuous fixed pitch running???power, frequency and voltage transients were comparable with those produced by typical load changes on the diesel system alone. In the fourth mode, variable pitch (constant power) control, a significant reduction in system damping sometimes occurred which gave rise to increased frequency and voltage perturbations under gusty wind conditions. Based on a linear model of the system it is shown that changes in control system settings could be made to improve damping.

Neutron absorber articles

Abstract: A neutron absorber element is composed of a metallic substrate bonded to a refractory coating containing gadolinium oxide. It has been found that these articles have excellent resistance to thermal shock, mechanical impact, abrasion, high temperature and water damage. These properties, in conjunction with its excellent nuclear properties, make these articles particularly well suited for use as neutron absorber elements in shipping containers for nuclear reactor fuel assemblies, and spent fuel storage racks.

Portable remote meter reading apparatus

Abstract: A portable remote meter reading apparatus is provided which communicates, via a power line conductor, with remote inaccessible electrical meters. A keyboard is provided to enable an operator to enter command and address information to identify a unique inaccessible meter. A baseband data message is formulated to include the unique address and command information. After being modulated with the high frequency carrier signal, the baseband data message is amplified and injected onto the power line conductor for receipt by a remote meter that is equipped with a transmitter and receiver. In response to the command message, the remote meter transmits electrical energy information for receipt by the present invention. The present invention incorporates receiver circuitry which filters lower frequencies from the incoming sinusoidal signal and hard limits the signal to provide a rectangular wave signal to a microprocessor which is capable of demodulating the signal and converting the incoming information into usable energy units, such as kilowatthours, for display on a visual display. Portable direct current power is provided in order to enable the present invention to be completely portable and not depend on the provision of power from external sources.

Low core loss rotating flux transformer

Abstract: A transformer utilizing a rotating flux for saturating the entire core. The transformer uses a core configured such that a vector sum of the induction produced by two windings in the core rotates through 360°. This is accomplished by arranging the component induction vectors to be perpendicular and the source voltages associated with each of the component induction vectors to be 90° out of phase. If the inductions are of equal magnitude and the vector sum is sufficient to saturate the core, rotation of the vector sum saturates the entire core and the transformer experiences a very low or nearly negligible hysteresis losses. Various topological configurations for the core, including a toroid, are described. The transformer windings can be arranged for single, two-phase, three-phase, or multi-phase operation.

Adaptive temperature control system for the supply of steam to a steam turbine

Abstract: The invention relates to a combined heat recovery steam generator and steam turbine. An adaptive temperature controller establishes a target temperature for controlling the boiler temperature so that the steam admitted on the boiler follows a constant enthalpy when trying to match temperature of steam and rotor temperature.

Magnetostatic waves and spin waves in layered ferrite structures

Abstract: Collective magnetic excitations are supported by multiple ferrite layers. The character of magnetostatic waves is calculated for such systems and is illustrated for three different layers variously spaced (accurate control of the delay characteristics is shown to be possible) as well as for very many similar layers equally spaced. For volume waves on many layers, collective spin-wave-like modes of long wavelength form a continuum that evolves smoothly into narrow bands characteristic of the layers at short wavelength. For surface waves, an excitation similar to the surface wave on a continuous medium appears when the spacing is less than the layer thickness, but a dense continuum of other excitations (not analogous to those of a uniform medium) always persists even for small spacings. This unexpected spectrum is related to a novel system of modes localized on the gaps.