Showing papers by "Westinghouse Electric published in 1989"

Adaptive speed identification for vector control of induction motors without rotational transducers

Abstract: A model-reference adaptive system (MRAS) for the estimation of induction motor speed from measured terminal voltages and currents is described. The estimated speed is used as feedback in a vector control system, thus achieving moderate bandwidth speed control without the use of shaft-mounted transducers. This technique is less complex and more stable than previous MRAS tacholess drives. It has been implemented on a 30 hp laboratory drive, where its effectiveness has been verified. >

Smart sensor system for diagnostic monitoring

Abstract: The present invention is a component monitoring system which includes all sensor and plant component monitoring at distributed plant locations close to the sensors which are the source of the signals to be analyzed. Minimally preconditioned analog sensor signals are multiplexed and further conditioned by a sensor signal preprocessor that adjusts the gain and filters the sensor signals before being applied to an analog-to-digital converter controlled by a data acquisition computer. The analog sensor signals are converted into digital samples and stored in a data memory of a digital signal processor using a direct memory access technique. The data acquisition computer also controls the selection of sensors, gain, etc., based on commands from a controller. The digital signal processor, once sufficient sensor data has been collected, performs appropriate processing using known digital signal processing techniques. This processed data is then sent to the controller for analysis to determine plant component condition. The analysis and processing routines can be changed by downloading a new routine from the controller. Once a sensor signal is processed, the controller selects the next sensor by transmitting an appropriate command to the data acquisition computer.

Frequency division multiplex guardband communication system for sending information over the guardbands

Abstract: A frequency division multiplex guardband communication system is provided which increases the communication capability of conventional FDM systems with negligible effect on overall system performance. The additional capacity is achieved through the use of guardbands which lie between the information bands of the FDM. To avoid interfering with recovery of the FDM information, the amount of new signal energy added to the individual guardbands is well below the guardband noise level.

Harmonics-causes, effects, measurements and analysis-update

Abstract: Rectification generates harmonic voltages and currents that can cause problems, e.g. insulation failures due to overheating and overvoltages, malfunction of solid-state equipment, communication interference, etc. The common addition of power factor correction capacitors to such a system generally increases the likelihood of such problems occurring. Online data acquisition and analysis of the harmonic content of system voltages and currents may be necessary to identify the cause properly and recommend a solution. In response to these problems, a field-proven portable harmonic-measurement/analysis system is described, as well as the advantages and versatility inherent in its use. This portable, computer-based system provides on-site data collection, precise harmonic identification via a fast Fourier transform, data analysis, and report preparation via a custom spreadsheet. Specific examples involving the application of this measurement/analysis system in the cement, steel, and carbon industries are presented. >

A statistically significant experimental technique for investigating microsegregation in cast alloys

Abstract: A simple, statistically significant experimental technique was developed to investigate microsegregation in a model cast Al-4.5 wt pct Cu alloy. This technique involves systematic composition measurements of the primary alloy phase of polished samples by use of the electron microprobe. The microprobe data were processed to obtain the detailed compositionvs fraction solid profile, which was an estimation of microsegregation of solute element in the sample. The number of data collected directly affected the statistical significance of the results. The results suggested that measurements of the order of 100 are adequate for obtaining statistically significant solute distribution profiles and, hence, for quantitatively determining the severity of microsegregation.

Method for associating text in automatic diagnostic system to produce recommended actions automatically

Abstract: A method for automatically generating recommended actions in response to a diagnosis uses a list ordered by impact of the actions. The list is evaluated using required evidence which must be supported by data and assumed evidence which must not be contradicted by the data. The method is applied to the diagnosis of malfunctions in equipment by an expert system rulebase. A correspondence is defined between text modules including the recommended actions and each of the schemata in the rulebase which produce a diagnosis. After a diagnosis is evaluated as true, the corresponding text modules are evaluated to produce a recommended action. The text modules can also be used for documentation of the rulebase.

Electrochemical cell apparatus having axially distributed entry of a fuel-spent fuel mixture transverse to the cell lengths

Abstract: An electrochemical apparatus (10) is made having a generator section (22) containing axially elongated electrochemical cells (16), a fresh gaseous feed fuel inlet (28), a gaseous feed oxidant inlet (30), and at least one gaseous spent fuel exit channel (46), where the spent fuel exit channel (46) passes from the generator chamber (22) to combine with the fresh feed fuel inlet (28) at a mixing apparatus (50), reformable fuel mixture channel (52) passes through the length of the generator chamber (22) and connects with the mixing apparatus (50), that channel containing entry ports (54) within the generator chamber (22), where the axis of the ports is transverse to the fuel electrode surfaces (18), where a catalytic reforming material is distributed near the reformable fuel mixture entry ports (54).

System and method for heat recovery in a combined cycle power plant

Abstract: A system and method are provided for recovering heat from the exhaust gas of a gas turbine operating in a combined cycle power plant. Heat is recovered by transferring it to feedwater supplied to a heat recovery steam generator. The heat recovery steam generator generates steam for expansion in a steam turbine, thereby producing additional rotating shaft power, and injection into the combustor of the gas turbine, thereby reducing nitrogen oxides in the exhaust gas. Feedwater from the condenser is entered directly into a feedwater heater in the heat recovery steam generator, thus avoiding the use of steam for feedwater heating. Acid corrosion is avoided by regulating the heat transferred from the exhaust gas to the feedwater heater in the event high sulfur fuel is burned in the gas turbine combustor.

Status tree monitoring and display system

Abstract: A display, a display method and an apparatus are disclosed which produce a summary display depicting function states using discrete state bars centered in one window of a two-window display. The other window on the summary display includes meters for the parameters along the active path of the status tree for the most relevant function as determined by the operator. Each meter indicates not only the current value of the parameter being monitored but the ranges of the different function states as they correspond to the parameter being displayed by the meter. Each meter also carries a data quality indicator. A second level display is provided which depicts the status tree with the active path highlighted allowing the operator to review the decision made by the status tree. The second level display also indicates the values of the parameters used in the decision-making process and includes a miniature version of the summary display that allows the operator to continuously monitor system summary status while reviewing the second level display. A third level display is also provided which depicts detailed information on the sensor values of the parameters being monitored as well as the exact questions being answered by decision trees of the process control monitoring system along with the answers. This third level display also includes a miniature version of the summary status display.

Turbine system having more failure resistant rotors and repair welding of low alloy ferrous turbine components by controlled weld build-up

Abstract: System for repairing worn surfaces of steam turbine components and especially high pressure turbine rotors, are disclosed. These systems include depositing a first layer of weld metal on a worn surface of the component, whereby a heat-affected zone is created. A second layer of weld metal is then deposited over the first layer using a greater amount of heat to temper at least a portion of the heat-affected zone produced by the first layer. The preferred embodiments include the use of gas tungsten arc welding for providing fine-grain size and more creep resistance, especially in the weld and heat-affected zone. The resulting build-up can be machined, for example into a blade fastening to produce a component having properties equal to or better than the base-metal alloy. The invention also provides a longer lasting turbine system, including rotors which have serrated steeples that are more resistant to failure.

A line voltage regulator/conditioner for harmonic-sensitive load isolation

Abstract: A technique is presented for the isolation of harmonic-sensitive loads from harmonic-producing loads, such as rectifiers and power converters. The solution, referred to as a line voltage regulator/conditioner (LVRC), utilizes a combination of a series and a parallel active power filter. The series filter isolates the sensitive loads on the output side of the LVRC from the nonlinear, distortion-producing loads on the input side by correcting for the harmonic voltage distortion present at the input. In addition, the series filter is utilized to regulate the output voltage. The parallel filter acts to generate the harmonic current required by the loads connected on the output side, therefore reflecting a linear load to the source. >

More creep resistant turbine rotor, and procedures for repair welding of low alloy ferrous turbine components

Abstract: A more creep resistant turbine rotor and novel methods for repairing worn surfaces of Cr-Mo-V steam turbine components are disclosed. These methods include specified alloy compositions and welding procedures that minimize weld stresses and cracking. These alloys exhibit improved creep and fatigue properties and are preferably deposited using a gas tungsten arc welding procedure. Bead sequencing, cooling side plates and the use of run-off tabs are also disclosed for minimizing welding defects in turbine rotors and discs.

Automated system to prioritize repair of plant equipment

Abstract: The system of the present invention uses the importance of a piece of malfunctioning equipment, the severity and the confidence level in a diagnosis to determine repair priority of the equipment by obtaining the product (46) of the confidence level (CF), importance (IMP) and severity (SEV). The these variables are determined by expert system rules. The severity is the reciprocal (88) of the time to failure. The importance (44) is the cost to repair the maximum damage when the malfunction continues. A malfunction can affect several pieces of equipment in combination, the severity and importance associated with each piece is combined (70) with the confidence and used to determine the repair priority. When the diagnosis of a malfunction is by malfunctioning sensors, the expected equipment life (40) and the availability (86) of sensors that provide a partial backup are considered in prioritizing sensor as well as equipment repair. When a primary piece of equipment is backed up (100), the effect of both pieces of equipment failing (106) is considered in prioritizing the repair. The system ranks the repair of all possible malfunctions on a common scale. The system gives a complete repair priority picture and allows the cost effectiveness to be maximized.

Extraction system with a pump having an elastic rebound inner tube

Abstract: An elastic rebound pump comprises a flexible inner tube having a substantial elastic rebound surrounded by a pump housing. The inner tube defines an inner chamber and the pump housing forms an outer chamber for confining a pump fluid. The pump allows pressurized gas or hydraulic fluid into the outer chamber to collapse the inner tube thereby discharging liquid from the inner chamber through an outlet opening. The pump alternately releases the pressurized fluid from the outer chamber thereby allowing the inner tube to rebound to a full configuration and draw liquid into the inner chamber through the inlet opening. By repeatedly allowing pump fluid into the outer chamber and sequentially releasing the pump fluid from the outer chamber, the pump produces a substantially steady flow of liquid. An extraction pump system includes the elastic rebound pump for removing liquid hydrocarbons from ground water collected in a well. The elastic rebound pump fits easily into small diameter wells and can be suspended above the liquid hydrocarbons in the well. An alternative extraction pump system includes a submersible pneumatic pump positioned within the ground water in the well for creating a cone of depression, and the elastic rebound pump and the submersible pump are driven simultaneously. In another disclosed extraction pump system, the elastic rebound pump is suspended within the housing of the submerged pneumatic pump. In still another disclosed extraction pump system, the elastic rebound pump is driven with pressurized ground water from a submersible pump.

Development of a Cladding Alloy for High Burnup

Abstract: An advanced Zircaloy cladding containing niobium has been developed and tested extensively both in long-term out-of-pile autoclave exposures and through high burnup irradiation in a pressurized water reactor (PWR) environment. Tubing of zirconium-based binary alloys containing 0.5, 1.0, and 2.5% niobium, and a quaternary composition containing tin, niobium, and iron was fabricated in such a manner that the second phase was fully precipitated, but with minimal particle growth. Autoclave testing in pure water and steam over the temperature range of 589 to 727 K indicates that all of the alloys except the 0.5% Nb have a lower post-transition corrosion rate than does Zircaloy-4, with the relative benefit increasing with temperature. Additional autoclave testing in LiOH solutions indicated a marked sensitivity of the Nb binaries to accelerated corrosion, and in these solutions only the Sn-Nb-Fe alloy was superior to Zircaloy-4. Experimental fuel assemblies with cladding of the advanced alloys were examined after one, three, and four cycles in the BR-3 reactor. Rod average burnups of up to 71 GWD/MTU were obtained with total residence times of up to 66 months. Results of post-irradiation examinations are given only for the Sn-Nb-Fe alloy as compared to Zircaloy-4. These examinations revealed that the Sn-Nb-Fe alloy showed the lowest overall corrosion, up to 50% better than Zircaloy-4 at the highest burnups, and was superior to the Zr-Nb binaries. The Sn-Nb-Fe alloy, called ZIRLO, also displayed lower irradiation growth and creep than the others.

Degradation of mechanical properties of Cr-Mo-V and 2.25Cr-1Mo steel components after long-term service at elevated temperatures

Abstract: The influence of operating temperature on in-service degradation of mechanical properties of high temperature stream turbine components has been investigated. Material samples for this study were taken from a Cr-Mo-V rotor and several 2.25Cr-1Mo cast steel components which had operated over 200,000 hours. The test results revealed that the degree of in-service degradation of strength, toughness, and the fracture appearance transition temperature of both steels were very sensitive to the service temperature. Both steels softened only when they were exposed at a temperature greater than 454°C (850°F) and the degree of softening increased with further increase in service temperature. In Cr-Mo-V steel, the loss in strength was accompanied by an improvement in ductility and toughness. Despite softening of 2.25Cr-1Mo steel in service, elevated temperature exposure resulted in a marked decrease in ductility and toughness. The loss of toughness in this steel was in part irreversible. In contrast, a severe increase in fracture appearance transition temperature, due to reversible temper embrittlement, occurred in both steels at a service temperature of around 427°C (800°F), but not at the highest service temperature. In fact, the Cr-Mo-V steel did not temper embrittle as a result of service exposure at the highest operating temperature investigated. These results are rationalized in terms of changes in microstructure and grain boundary chemistry that occur in service as a function of operating temperature.

Efficiency combined cycle power plant

Abstract: The efficiency of a combined cycle power plant is improved by preheating fuel supplied to a combustion turbine. The flow rate of feed water through an economizer section of a heat recovery steam generator is increased, and the excess flow, over that required to sustain saturated steam production in an evaporator section, is flowed through a heat exchanger to preheat the fuel.

Laser Velocimeter Measurements in a Centrifugal Flow Pump

Abstract: A laser velocimeter was used to measure velocities within the impeller and volute of a centrifugal pump. Measurements were made at four circumferential and eight radial positions. Flow rates ranged from 40 to 105 percent of design flow. Blade-toblade prof iles for the four circumferential positions indicate the flow is circumferentially asymmetric around the pump even at the design flow. Blade-to-blade profiles show normal blade loading for 90 percent of the impeller, with reverse and zero loading occurring in the outer 10 percent of the impeller for design flow. Reversed blade loading over greater portions of the impeller is seen at off-design flow. At 40 percent of design flow, recirculating flow within the impeller was found. Axial traverses across the impeller show the radial velocity profile skewed toward the hub surface at the inlet and away from the hub surface at the exit. The stagnation point on the tongue moved from the outside to the inside as the flow rate was increased from 40 to 105 percent of design. Values for slip range from 0.96 to 0.71 from the in­ let to the exit.

Product detector for a steady visual evoked potential stimulator and product detector

Abstract: An automated visual testing system is disclosed which presents an alternating steady state visual stimulus to a patient through an optical system that modifies the stimulus image. As the image changes, the patient produces evoked potentials that change. The evoked potentials are detected by a product detector which produces the amplitude of the evoked potentials. The product detector includes filters which isolate the patient's evoked potentials, a modulator which detects the response using the stimulus source frequency and a demodulator that determines the amplitude of the response. The product detector detects the level of the steady state evoked potential signals even in the presence of substantial background noise and extraneous electroencephalograhic signals. These detectors can be used to monitor the evoked potential produced by visual, aural or somatic steady state stimuli. The components described above can be used to produce a system that can determine to which of several different displays an observer is paying attention by providing images that blink at different frequencies and product detectors for each of the stimulus frequencies. The product detector producing the highest output indicates the display upon which the observer is focused.

Turbine blade fatigue monitor

Abstract: An on-line vibratory fatigue monitor measures displacement of an object such as the blade of a turbine rotor to generate a displacement signal and calculates accumulated fatigue in the object in dependence upon the displacement signal. The displacement of the object may be detected by passive proximity probes which generate signals indicative of changes in magnetic flux or capacitance between the sensor and the turbine blade. An analog/digital converter converts the signals from the probes to digital signals indicating displacement of the turbine blades. The digital signals are processed, preferably by taking a Hilbert transform, to detect the amplitude envelope and instantaneous frequency of the displacement. The amplitude and frequency are combined with steady state stress on the object to determine fatigue usage which is accumulated by constantly monitoring vibratory displacement and changes in the steady state stress.

Digital neural network processing elements

Abstract: A preprocessing device is disclosed which performs a linear transformation or power series expansion transformation on the input signals to a neural network node. The outputs of the preprocessing device are combined as a product of these linear transformations and compared to a threshold. This processing element configuration, combining a transformation with a product and threshold comparison, performs non-linear transformations between input data and output results. As a result, this processing element will, by itself, produce both linearly and non-linearly separable boolean logic functions. When this processing element is configured in a network, a two layer neural network can be created which will solve any arbitrary decision making function. This element can be configured in a probability based binary tree neural network which is validatable and verifiable in which the threshold comparison operation can be eliminated. The element can also be implemented in binary logic for ultra high speed. If the linkage element performs the power series expansion, a universal or general purpose element is created.

Solder joint inspection system and method

Abstract: The invention is an automated solder joint inspection system for determining the quality of a specular soldered joint through examination of the shape of the joint surface using a series of point light sources and the associated highlight reflections from the joint surface. The light from point light sources, which is directed toward the solder joint, is reflected in a pattern from the solder joint to an array of light responsive transducers from at least one location. Utilizing the intensity values from the light responsive transducer array, the surface orientation of the solder joint at a number of points is determined. The solder joint is evaluated in one of two ways. In one way, using known surface features of solder joints along with curve fitting techniques, a series of grid maps is mathematically interpreted to reconstruct the solder joint surface. A rule-based system, through comparison with acceptable solder joint surface features, evaluates and classifies the joint for an acceptability determination. In another way the surface orientation is used to generate an Extended Gaussian Image of the joint and the features of this are analyzed.

Mounting of integral platform turbine blades with skewed side entry roots

Abstract: Method and apparatus for assembling integral platform blade groups to a rotor of a steam turbine in which the platform roots are skewed with respect to the axis of the turbine. The platform roots are formed to define a set of spaced grooves and steeples are formed on the rotor to mate with the platform roots. Grooves on the platform and in the rotor are alignable to accept a connecting member when the steeples are aligned in abutting relationship with platform roots. The connecting member joins the blade group to the rotor. In one form, the bearing surfaces of the steeples, roots and connecting member are formed to lie on one or more circles circumscribing the rotor axis.

Solderless printed wiring board module and multi-module assembly

Abstract: A solderless printed wiring board module for receiving and securing surface mounted solderless electronic component carrier and electronic components without carrier upon a printed wiring board, the module also providing a heat transfer path to a surface away from the printed wiring board and the module further adaptable to electrical and mechanical attachment to similar modules placed adjacent to said module to form a multi-module assembly.

Cavity-down chip carrier with pad grid array

Abstract: The invention is an improved chip carrier assembly utilizing a cavity-down chip carrier with a pad grid array wherein the IC chip within the chip carrier is mounted against a surface opposite the PWB to which the chip carrier is attached such that heat transfer from the IC chip may occur along a short path to a heat sink such that a large heat transfer rate is possible Furthermore, the apparatus utilizes an alignment and electrical connection means between the contact pads of the chip carrier and a PWB to which the chip carrier is attached to compensate for shrinkage variation which occurs during the chip carrier fabrication process Furthermore, within the cavity of the chip carrier there is space for additional components such as a decoupling capacitors This permits the design of an apparatus providing better heat transfer properties, more accurate contact pad locations and the option of including within the chip carrier components which in the past had been mounted outside of the chip carrier