Showing papers by "Westinghouse Electric published in 1997"

Static Synchronous Series Compensator: A Solid-State Approach to the Series Compensation of Transmission Lines

Abstract: This paper describes an active approach to series line compensation, in which a synchronous voltage source, implemented by a gate turn-off thyristor (GTO) based voltage-sourced inverter, is used to provide controllable series compensation. This compensator, called static synchronous series compensator (SSSC), can provide controllable compensating voltage over an identical capacitive and inductive range, independently of the magnitude of the line current. It is immune to classical network resonances. In addition to series reactive compensation, with an external DC power supply it can also compensate the voltage drop across the resistive component of the line impedance. The compensation of the real part of the impedance can maintain high X/R ratio even if the line has a very high degree of series compensation. Concurrent and coordinated modulation of reactive and real compensation can greatly increase power oscillation damping. The paper discusses the basic operating and performance characteristics of the SSSC, and compares them to those characterizing the more conventional compensators based on thyristor-switched or controlled series capacitors. It also presents some of the results of TNA simulations carried out with an SSSC hardware model.

Environmental/economic dispatch using fuzzy logic controlled genetic algorithms

Abstract: The paper presents the application of a fuzzy logic controlled genetic algorithm (FCGA) to power system environmental/economic dispatch. The authors first propose an improved genetic algorithm with two fuzzy controllers based on some heuristics to adaptively adjust the crossover probability and mutation rate during the optimisation process. The implementation of the fuzzy crossover and mutation controllers is described. The proposed FCGA can be applied to wide range of optimisation problems. The validity of the proposed algorithm is illustrated on environmental/economic dispatch of a six-generator power system. Its performance is compared with conventional GAs and the Newton-Raphson method. The results are very encouraging.

Environmentally-sealed, convectively-cooled active matrix liquid crystal display (LCD)

Abstract: A display unit for use with a computer and a power supply, includes an environmentally-sealed enclosure having a removable cover, and housing a liquid crystal display screen, the removable cover serving as an integral heat sink for the power supply, the power supply being mounted on the internal surface of the cover. Further, a backlighting device backlights the display screen, and a cooling plenum conductively and convectively cools the backlighting device, the backlighting device being mounted directly on a surface of the plenum.

Nuclear fuel assembly

Abstract: The invention relates to a fuel assembly for a boiling water reactor which is adapted, during operation of the reactor, to allow water to flow upwards through the fuel assembly while absorbing heat from a plurality of fuel rods, whereby part of the water is transformed into steam The fuel assembly comprises a steam channel through which the steam flows through the fuel assembly The steam channel (16a, 16b, 16c, 16d) consists of an empty volume which at least extends through part of the fuel assembly The fuel assembly is designed such that the water and the steam are brought to rotate around the steam channel whereby the water is thrown away from the steam channel whereas the steam which is separated from the water flows upwards through the steam channel

Solid oxide fuel cell generator with removable modular fuel cell stack configurations

Abstract: A high temperature solid oxide fuel cell generator produces electrical power from oxidation of hydrocarbon fuel gases such as natural gas, or conditioned fuel gases, such as carbon monoxide or hydrogen, with oxidant gases, such as air or oxygen. This electrochemical reaction occurs in a plurality of electrically connected solid oxide fuel cells (120) bundled and arrayed in a unitary modular fuel cell stack disposed in a compartment in the generator container. The use of a unitary modular fuel cell stack in a generator is similar in concept to that of a removable battery. The fuel cell stack (100) is provided in a pre-assembled self-supporting configuration where the fuel cells are mounted to a common structural base (102) having surrounding side walls (130) defining a chamber. Associated generator equipment may also be mounted to the fuel cell stack configuration to be integral therewith, such as a fuel (106) and oxidant supply and distribution systems, fuel reformation systems (108), fuel cell support systems (116), combustion, exhaust and spent fuel recirculation systems, and the like. The pre-assembled self-supporting fuel cell stack arrangement allows for easier assembly, installation, maintenance, better structural support and longer life of the fuel cells contained in the fuel cell stack.

Apparatus and methods for storing and releasing hydrogen

Abstract: A rechargeable device (20) that stores and discharges hydrogen is described. The device stores hydrogen in a solid form and supplies hydrogen as a gas when needed. The solid storage medium (36) may be metal hydride in a ground particle form that avoids the need for compaction or other treatment. Dividers (28) partition a container into separate chambers, each provided with a matrix (26), formed from an appropriate material like a thermally-conductive aluminum foam, which forms a number of cells (27). For proper chamber size, the ratio of chamber length to container diameter should be between about 0.5 and 2. Metal hydride particles (or other hydrogen storage medium) may be placed within the cells, which help prevent excessive particle settling. The container is provided with a hydrogen transfer port (32) through which hydrogen gas passes upon either discharging from or charging of the metal hydride particles. A filter may be placed within the port to allow hydrogen to flow but prevent particles from escaping. A heat transferring surface (23) is formed by, for instance, a channel that is thermally coupled with the aluminum foam. Fluid flows through the channel (40) to deliver or remove heat during the respective hydrogen discharging or charging processes.

Operation of /spl plusmn/100 MVAr TVA STATCON

Abstract: In 1995 a /spl plusmn/100 MVA static synchronous compensator (STATCON) was commissioned for the Tennessee Valley Authority (TVA) at the Sullivan substation in North-Eastern Tennessee, USA. This was an historic milestone in the initiative for flexible AC transmission systems (FACTS) promoted by the Electric Power Research Institute (EPRI). The TVA STATCON is the first of its kind, using GTO thyristor valves, to be commissioned in the United States, and is currently the largest installation of this type in the world. Commissioning tests have now been completed and the STATCON is operating continuously online. The demonstrated performance of the equipment has either met or exceeded expectations in all areas and has proven beyond doubt the viability of this type of equipment in high power transmission systems. This paper briefly reviews the STATCON installation and reports on the static and dynamic performance observed during commissioning.

Distribution network reconfiguration for loss reduction using fuzzy controlled evolutionary programming

Abstract: Network reconfiguration for loss reduction in distribution systems is a very important way to save energy. However, due to its nature it is an inherently difficult optimisation problem. A new type of evolutionary search technique, evolutionary programming (EP), has been adopted and improved for this particular application. To improve the performance of EP, a fuzzy controlled EP (FCEP), based on heuristic information, is first proposed. The mutation fuzzy controller adaptively adjusts the mutation rate during the simulated evolutionary process. The status of each switch in distribution systems is naturally represented by a binary control parameter 0 or 1. The length of string is much shorter than those proposed by others. A chain-table and combined depth-first and breadth-first search strategy is employed to further speed up the optimisation process. The equality and inequality constraints are imbedded into the fitness function by penalty factors which guarantee the optimal solutions searched by the FCEP are feasible. The implementation of the proposed FCEP for feeder reconfiguration is described in detail. Numerical results are presented to illustrate the feasibility of the proposed FCEP.

Enhanced distributed power

Abstract: A train throttle and brake control apparatus is provided for use in a train having a master locomotive and one or more slave locomotives remotely located in the train. In a first embodiment, the apparatus includes a train force calculator which approximates train coupler forces based on computations as a function of the track topography. In a second embodiment, a coupler sensor is provided which senses the forces transmitted by the couplers on the slave locomotives. In either embodiment, a position determining device is included which provides a position signal based on the position of the train. A storage device stores a track database containing track topography information. A controller uses the coupler force computations or measurements, the position information, the track topography information, train consist information, and locomotive control settings to generate slave control signals which are provided to the slave locomotives through a communication device.

Combustor with two stage primary fuel tube with concentric members and flow regulating

Abstract: A combustor for a gas turbine having a centrally located fuel nozzle and inner, middle and outer concentric cylindrical liners, the inner liner enclosing a primary combustion zone. The combustor has an air inlet that forms two passages for pre-mixing primary fuel and air to be supplied to the primary combustion zone. Each of the pre-mixing passages has a circumferential array of swirl vanes. A plurality of primary fuel tube assemblies extend through both pre-mixing passages, with each primary fuel tube assembly located between a pair of swirl vanes. Each primary fuel tube assembly is comprised of two tubular members. The first member supplies fuel to the first pre-mixing passage, while the second member, which extends through the first member, supplies fuel to the second pre-mixing passage. An annular fuel manifold is divided into first and second chambers by a circumferentially extending baffle. The proximal end of the first member is attached to the manifold itself while the proximal end of the second member is attached to the baffle. The distal end of the first member is attached directly to the second member at around its mid-point. The inlets of the first and second members are in flow communication with the first and second manifold chambers, respectively. Control valves separately regulate the flow of fuel to the two chambers and, therefore, to the two members of the fuel tube assemblies, thereby allowing the flow of fuel to the first and second pre-mixing passages to be separately controlled.

Distributed positive train control system

Abstract: A system for controlling train movement uses a distributed architecture. Wayside controllers receive signals from individual trains, including position information derived from a navigation system. The wayside controllers interface with a central train control network, and coordinate local train movement including the issuance of incremental authorities.

Intra-train radio communication system

Abstract: A radio-based system for a train including a lead transceiver unit and multiple remote transceiver units. The lead transceiver unit initiates a command by sending a command message. Each of the remote transceivers receiving the command message transmits a reply message which repeats the command message and contains the status of the sending remote. Remote transceivers not receiving the lead transceiver's transmitted command message, but receiving a reply message from one of the other remote transceivers, transmit a reply message containing the remote's status. The lead transceiver detects whether reply messages are received from the remote transceivers and may transmit a request in response. One or more remote transceivers may store and re-transmit reply messages from other transceivers in response to the request.

Integrated cab signal rail navigation system

Abstract: The cab signal and rail navigation systems of a railway locomotive are combined to form a single integrated system capable of acting as an automatic train protection system. The train travels along a railway route equipped with a wayside signaling system that features a multiplicity of wayside signal devices. Each wayside signal device provides to the cab signal system a cab signal inclusive of signal aspect information as to how the train should proceed along a particular segment of the railway route. When the train is traveling on a segment of track from which the cab signal is available, the cab signal system receives the cab signal via the AC track circuit disposed on the rails as the train approaches each wayside signal device. After filtering and decoding the electrical cab signal, the cab signal system communicates the deciphered signal aspect information to the rail navigation system. The rail navigation system determines whether signal aspect information should be available from the particular track segment the train is encountering and thus whether and how the brakes of the train will be operated thereon should the train engineer be required and fail to operate the brakes according to one or more braking profiles calculated by the system. The integrated system operates as an automatic train protection system whether the wayside signaling system provides cab signal coverage continuously or noncontinuously throughout the railway route.

Closed loop air cooling system for combustion turbines

Abstract: Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor (22, 26) and delivered to passages internal to one or more of a combustor and turbine hot parts (100). The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts.

Technetium Speciation in Cement Waste Forms Determined by X-ray Absorption Fine Structure Spectroscopy

Abstract: The chemistry of technetium in cement waste forms has been studied with X-ray absorption fine structure (XAFS) spectroscopy. Using the Tc /f-edge X-ray absorption near-edge structure (XANES) as a probe of the technetium speciation, our results show that partial reduction of the pertechnetate ion, TcOj, takes place in the presence of the cement additive, blast fumace slag (BFS). The addition of the reducing agents FeS, NazS, and NaHjPOz produces more extensive reduction of TcOl, while the Compounds FeO, Fe304, and MnjOi are observed to be unreactive. The extended X-ray absorption fine structure (EXAFS) data for the BFS, Na^S, and FeS treated cements indicate the presence of Tc Clusters possessing first shell S coordination. For the Na2S and FeS additives, Tc-Tc interactions are detected in the EXAFS demonstrating an extended structure similar to that of TcSa. The EXAFS spectrum of the NaHzPOj treated cement reveals T c O and Tc-Tc interactions that resemble those found in the structure of TcO,.

Information display system

Abstract: A functional approach to an information display system that enables a fast and easy understanding of the status of a complex process. The display screen is organized by process goals. Each process goal is then tied to a number of process objectives which directly relate individually to the goals. The objectives are in turn tied to the process functions which must be substantially maintained in order to achieve the respective objectives. A display of control functions related to each process function is mapped onto the regional displays. The individual display elements use a combination of coded background color, border color and other indicia of information, e.g., mimics, meters, etc. to present a significant amount of information about the status of the process and its components in a manner that is readily absorbed and easily understood.

Paradigms for Intelligent Interface Design

Abstract: Publisher Summary The term “intelligent interface” has grown to be an umbrella term that covers a wide and diverse range of topics including dialog understanding, user modeling, adaptive interfaces, cooperative person-machine approaches to problem-solving and decision making, and use of machine intelligence to create more effective explanations and visualizations. This chapter uses the term “intelligent interface” to refer to both the design of user interfaces for intelligent systems and the design of user interfaces that utilize knowledge-based approaches. The chapter examines three broad paradigms for development of intelligent interfaces: intelligent interfaces as cognitive tools that can be utilized by practitioners in solving their problems; intelligent interfaces as members of cooperative person-machine systems that jointly work on problems and share task responsibility; and intelligent interfaces as representational aids that dynamically structure the presentation of information to make key information perceptually salient. The chapter begins with a review of some of the limitations associated with the stand-alone machine problem-solver paradigm that stimulated exploration of alternative paradigms for deployment of machine intelligence. This is followed by a description of each of the three paradigms for intelligent interface design. In each case, examples of systems are presented representing that paradigm and some of the key design principles that derive from that paradigm.

Train separation detection

Abstract: A train separation detector for a distributed power control system in railroad trains and trains with an installed Electronic Control Pneumatic (ECP) brake system uses the distance traveled input from an axle drive generator or similar device to compute the speed of the lead locomotive and the speed of the remote locomotives and/or ECP brake system equipped cars and also the distance traveled by the lead locomotive and the remote locomotives and/or ECP brake system equipped cars per unit of time. Normally, both the distance traveled and the speed of the lead and remote locomotives and/or ECP brake system equipped cars will, on average, be the same since they are in the same train. If there is a separation, however, both the distance traveled and the speed of the lead and remote locomotives and/or ECP brake system equipped cars will be different to the extent that there is a train separation. By comparing the speed and distance traveled of the lead and remote locomotives and ECP brake system equipped cars, the lead locomotive will be able to detect train separation and take appropriate action.

Hydrogen embrittlement of Ni-Cr-Fe alloys

Abstract: The purpose of this work was to investigate the role of chromium on hydrogen embrittlement of Ni-Cr-Fe alloys and thus to develop a better understanding of the low-temperature stress corrosion cracking (SCC) phenomenon. The effect of chromium on hydrogen embrittlement was examined using tensile tests followed by material evaluation via scanning electron microscopy (SEM) and light optical microscopy. Four alloys were prepared with chromium contents ranging from 6 to 35 wt pct. In the uncharged condition, ductility, as measured by the percent elongation or reduction in area, increased as the alloy chromium content increased. Hydrogen appeared to have only minor effects on the mechanical properties of the low-chromium alloys. The addition of hydrogen had a marked effect on the ductility of the higher-chromium alloys. In the 26 pct chromium alloy, the elongation to failure was reduced from 53 to 14 pct, with a change in fracture mode from mixed ductile dimple and ductile intergranular failure to a brittle appearing intergranular failure. A maximum in embrittlement was observed in the 26 pct Cr alloy. The maximum in embrittlement coincided with the minimum in stacking-fault energy. It is proposed that the increased hydrogen embrittlement in the high-chromium alloys is due to increased slip planarity caused by the lower stacking-fault energy. Slip planarity did not appear to affect the fracture of the uncharged specimens.

Compatibility of FM hybrid in-band on-channel (IBOC) system for digital audio broadcasting

Abstract: A robust in-band on-channel (IBOC) digital audio broadcast (DAB) system for improved performance over existing FM broadcasting is under development by Westinghouse for USA Digital Radio. Both the analog FM and the DAB signals are transmitted simultaneously in the FM hybrid IBOC system. Broadcasters can simultaneously transmit both analog and digital signals within the allocated channel mask, allowing full compatibility with existing analog receivers. It is shown here that the solution is tolerant of interference from adjacent channels, or interference from the co-channel analog transmission, even in a multiple station, strong-signal urban market. Although the primary focus of this paper is to discuss the compatibility issues between the existing FM and the DAB signals, the paper also briefly describes spectral occupancy, power ratios, modulation formats, and coding, as well as the introduction of frequency and time diversity.

Apparatus for cooling a gas turbine airfoil and method of making same

Abstract: An airfoil for use in a turbomachine such as a stationary vane in a gas turbine. The airfoil has a plurality of longitudinally extending ribs in its trailing edge region that form first cooling fluid passages extending from the airfoil cavity to the trailing edge of the airfoil. The first cooling fluid passages are tapered so that their height and width decrease as they extend toward the trailing edge. Turbulating fins are spaced along the length of each passage to increase the heat transfer. The ribs have a plurality of radially extending passages spaced along their length so as to form an array of interconnected longitudinal and radial passages. The airfoil is formed by a casting process using a core that has longitudinal and radial fingers that correspond to the longitudinal and radial passages of the airfoil.

Characterization of Colloids Mobilized from Southeastern Coastal Plain Sediments

Abstract: Two subsurface samples representing highly weathered sediments of the Upper Coastal Plain (Aiken, SC) that differed in Fe-oxide content (7.3 vs 35.9 g Fe kg -1 ) were evaluated in terms of mobile colloid generation in response to changes in solution composition. In repacked columns, the two sediments were leached (∼0.72 m d -1 Darcy velocity) with either 0.001 N NaCI or CaCl 2 solutions for 10 pore volumes followed by 10 pore volumes of deionized water. Bulk clay mineralogy from the two samples and suspensions generated in the column studies was characterized by energy dispersive X-ray analysis (EDXA) using a field-emission scanning electron microscope (SEM). SEM results were confirmed by selected-area electron diffraction (SAED) and EDXA in a transmission electron microscope. In column experiments, the sample lower in Fe oxide displayed increased effluent turbidity that coincided with a decrease in effluent pH during injection of the CaCl 2 solutions. In contrast, no effluentturbiditywas observed during the leaching of NaCl solutions. The sample higher in iron oxide displayed greater effluent turbidity from the onset of leaching that decreased over the duration of injection for both the CaCl 2 and NaCl solutions. Colloids generated from both materials displayed positive electrophoretic mobilities, confirming the importance of iron oxides in controlling dispersion and surface charge properties of the mobile colloids. Minor differences in the clay mineralogy (i.e., iron oxide/kaolinite content) between the samples were reflected in both their sensitivity to pore-solution composition and the relative degree of dispersion observed for each sample. Electron microscopy, EDXA, and thermal gravimetric analysis (TGA) confirmed that the mobile colloids consisted mainly of submicron sized Al-rich goethite, with lesser amounts of kaolinite,the predominate layer silicate of the bulk sediments, and varying amounts of crandallite.

Closed-loop air cooling system for a turbine engine

Abstract: Method and apparatus are disclosed for providing a closed-loop air cooling system for a turbine engine. The method and apparatus provide for bleeding pressurized air from a gas turbine engine compressor for use in cooling the turbine components. The compressed air is cascaded through the various stages of the turbine. At each stage a portion of the compressed air is returned to the compressor where useful work is recovered.

Distributed power train separation detection

Abstract: A train separation detector for a distributed power control system in railroad trains uses the distance traveled input from an axle drive generator or similar device to compute the speed of the lead locomotive and the speed of the remote locomotives and also the distance traveled by the lead locomotive and the remote locomotives per unit of time. Normally, both the distance traveled and the speed of the lead and remote locomotives will, on average, be the same since they are in the same train. If there is a separation, however, both the distance traveled and the speed of the lead and remote locomotives will be different to the extent that there is a train separation. By comparing the speed and distance traveled of the lead and remote locomotives, the distributed power system will be able to detect train separation and take appropriate action.

Robust modem and coding techniques for FM hybrid ICOC DAB

Abstract: The design of robust modem and FEC (forward error correction) code techniques with application to the transmission of an FM hybrid analog/digital in-band on-channel (IBOC) digital audio broadcast (DAB) signal is presented here. The FEC codes are derived from an original lower rate convolutional code (R=1/3). The original code is segmented into a pair of "complementary" components, which form independent codes, each with a higher rate (less redundancy) than the base code. The exploitation of channel state information (CSI) and special interleaving techniques are described for application to FM hybrid IBOC DAB with its unique interference environment and selective fading due to multipath. Simulation results confirm the robustness of the design.

Combustion turbine modular cooling panel

Abstract: A modular cooling panel for cooling a turbine member is provided. The cooling panel comprises a first panel having a relative width, relative length, upper surface and lower surface. The upper surface defines at least one corrugated portion traversing along a portion of the relative width of the upper surface. The corrugated portion defines a cooling flow channel through which a cooling fluid can travel to cool the turbine member. The cooling flow channel has at least one inlet opening for enabling the cooling fluid to enter into the cooling flow channel. The lower portion surface of the first panel is adapted to be coupled in fluid communication with the turbine member.

Power operator for sliding plug doors

Abstract: A powered operator for sliding plug doors mounted on a movable carriage mounted overhead of an opening in the side wall of a transit vehicle, said doors including a single electric prime mover driving dual helical drives, each operating a door hanger attached to a single door panel over and away from said opening and for moving said carriage out of said side wall pocket. Door hangers used provide controlled deflection of door panels when in a fully open position. Drive linkages lock door panels when in a plugged position. The operator also provides guidance for the lower edge of said door panels during plugging and unplugging operations. Control elements and a central controller provides sequential door panel movement into and out of a pocket in the transit car side wall.