Showing papers by "Westinghouse Electric published in 1998"

SSSC-static synchronous series compensator: theory, modeling, and application

Abstract: This paper describes the theory and the modelling technique of a flexible alternating current transmission systems (FACTS) device, namely, static synchronnous series compensator (SSSC) using an Electromagnetic Transient Program (EMTP) simulation package. The SSSC, a solid-state voltage source inverter coupled with a transformer, is connected in series with a transmission line. An SSSC injects an almost sinusoidal voltage, of variable magnitude, in series with a transmission line. This injected voltage is almost in quadrature with the line current, thereby emulating an inductive or a capacitive reactance in series with the transmission line. The emulated variable reactance, inserted by the injected voltage source, influences the electric power flow in the transmission line.

Operation of the unified power flow controller (UPFC) under practical constraints

Abstract: The UPFC is the most versatile and complex power electronic equipment that has emerged for the control and optimization of power flow in electrical power transmission systems. It offers major potential advantages for the static and dynamic operation of transmission lines, but it brings with it major design challenges, both in the power electronics and from the perspective of the power system. As the UPFC transitions from concept to full-scale power system implementation, the control and protection of this sophisticated equipment are of primary concern. This paper describes the basic control, sequencing and protection philosophies that govern the operation of the UPFC, subject to the practical constraints encountered in an actual high power installation. The operation of the UPFC is illustrated with representative results from a TNA study, undertaken jointly by the Electric Power Research Institute (EPRI), Western Area Power Administration (WAPA) and Westinghouse Science and Technology Center (STC).

UPFC-unified power flow controller: theory, modeling, and applications

Abstract: This paper describes the theory and the modeling technique of a flexible alternating current transmission systems (FACTS) device, namely, unified power flow controller (UPFC) using an Electromagnetic Transients Program (EMTP) simulation package. The UPFC, in this paper, consists of two solid-state voltage source inverters which are connected through a common DC link capacitor. Each inverter is coupled with a transformer at its output. The first voltage source inverter, known as a static synchronous compensator (STATCOM), injects an almost sinusoidal current, of variable magnitude, at the point of connection. The second voltage source inverter, known as a static synchronous series compensator (SSSC) injects an almost sinusoidal voltage, of variable magnitude, in series with the transmission line. This injected voltage can be at any angle with respect to the line current. The exchanged real power at the terminals of one inverter with the line flows to the terminals of the other inverter through the common DC link capacitor. In addition, each inverter can exchange reactive power at its terminals independently. The functionalities of the models have been verified.

AEP UPFC project: installation, commissioning and operation of the /spl plusmn/160 MVA STATCOM (phase I)

Abstract: American Electric Power (AEP) has selected its Inez Substation in eastern Kentucky for the location of the world's first Unified Power Flow Controller (UPFC) installation. Comprising two /spl plusmn/160 MVA voltage-sourced GTO-thyristor-based inverters, this installation is not only the first practical demonstration of the UPFC concept, but also by far the highest power GTO-based Flexible AC Transmission Systems (FACTS) equipment ever installed. The installation will be the first demonstration of this type of equipment connected in series with a transmission line. The project is a collaborative effort between AEP, the Westinghouse Electric Corporation, and the Electric Power Research Institute (EPRI), and has been divided into two phases corresponding to the installation of the shunt- and series-connected inverters respectively. Phase I (installation and commissioning of the shunt inverter (STATCOM)) was completed successfully in July, 1997, and the STATCOM is now operational. Phase II is scheduled for completion in early 1998. This paper gives a brief background to the project, describes the installation and special features of the equipment, and reports on the Phase I commissioning and STATCOM operation.

Development of a silicon carbide radiation detector

Abstract: The radiation detection properties of semiconductor detectors made of 4H silicon carbide were evaluated. Both Schottky and p-n junction devices were tested. Exposure to alpha particles from a /sup 238/Pu source led to robust signals from the detectors. The resolution of the Schottky SiC detector was 5.8% (FWHM) at an energy of 294 keV, while that of the p-n junction was 6.6% (FWHM) at 260 keV. No effect of temperature in the range of 22 to 89/spl deg/C was observed on the characteristics of the /sup 238/Pu alpha-induced signal from the SiC detector. In addition, testing in a gamma field of 10,000 rad-Si h/sup -1/ showed that the alpha-induced signal was separable from the gamma signal.

Rail vision system

Abstract: A rail vision system visually reads signal aspect information from each wayside signal device of a wayside signaling system. It also warn a train operator of the more restrictive signal aspects and imposes a penalty brake application should the train operator fail to acknowledge the warning. Each wayside signal device communicates from a railway operating authority information including directions as to how the train should proceed along the upcoming segment of railway track. The rail vision system includes a signal locating system and a rail navigation system. The signal locating system isolates visually the upcoming wayside signal device and reads the information therefrom as the train approaches thereto. The rail navigation system determines the position that the train occupies on the railway track and provides the signal locating system with data as to the whereabouts of the upcoming wayside signal device relative to the position of the train. This enables the signal locating system to isolate visually the upcoming wayside signal device and to provide the information read therefrom to the rail navigation system. The rail navigation system can then warn the train operator of the more restrictive signal aspects, and should the train operator fail to acknowledge the warning, impose a penalty brake application.

Turbine blades made from multiple single crystal cast superalloy segments

Abstract: Large gas turbine blades (10) made from separate cast segments (12, 14. 16, 18) of superalloys are disclosed. The turbine blade is designed such that bond lines between adjacent segments are placed in low stress regions of the blade. The cast superalloy segments of the blades are aligned and fitted together with specified tolerances. The turbine blade segments are then joined by transient liquid phase bonding, followed by a controlled heat treatment which produces the desired microstructure in the bond region. The method allows for the production of large, high quality turbine blades (10) by joining small, high quality cast superalloy sections (12, 14, 16, 18), in comparison with prior attempts to cast large turbine blades as single pieces which have produced very low yields and high individual component costs.

High temperature insulation for ceramic matrix composites

Abstract: A ceramic composition is provided to insulate ceramic matrix composites under high temperature, high heat flux environments. The composition comprises a plurality of hollow oxide-based spheres of various dimensions, a phosphate binder, and at least one oxide filler powder, whereby the phosphate binder partially fills gaps between the spheres and the filler powders. The spheres are situated in the phosphate binder and the filler powders such that each sphere is in contact with at least one other sphere. The spheres may be any combination of Mullite spheres, Alumina spheres, or stabilized Zirconia spheres. The filler powder may be any combination of Alumina, Mullite, Ceria, or Hafnia. Preferably, the phosphate binder is Aluminum Ortho-Phosphate. A method of manufacturing the ceramic insulating composition and its application to CMC substrates are also provided.

Annular premix section for dry low-NOx combustors

Abstract: An annular premix section that reduces NO x and CO emissions of a gas turbine combustor by providing a more homogeneous fuel/air mixture for main stage combustion is provided. A gas turbine combustor according to the present invention includes a nozzle housing, a main fuel nozzle, and a main fuel swirler. A main combustion zone is located adjacent to the nozzle housing. The main fuel nozzle extends through the nozzle housing and is attached to a nozzle housing base. The tip of the main fuel nozzle is located downstream of the nozzle housing base. The main fuel swirler surrounds a portion of the main fuel nozzle, with a downstream end of the main fuel swirler located downstream of a main fuel injection port and upstream of the main fuel nozzle tip. The main fuel swirler is adapted to receive a flow of compressed air and to mix a fuel with the flow of compressed air to form a fuel/air mixture flow. An annular premix section, adjacent to the downstream end of the main fuel swirler, is adapted to receive and expand the fuel/air mixture flow. A contraction zone is located downstream of the premix section and upstream of the main combustion zone. The contraction zone is adapted to increase the velocity of the fuel/air mixture flow into the main combustion zone.

Main stage fuel mixer with premixing transition for dry low Nox (DLN) combustors

Abstract: A main stage fuel mixer that reduces NO x and CO emissions of a gas turbine combustor by providing a more homogeneous fuel/air mixture for main stage combustion is provided. A gas turbine combustor according to the present invention includes a nozzle housing having a nozzle housing base, a plurality of main nozzles, and a main stage fuel mixer. A main combustion zone is located adjacent to the nozzle housing. Each main nozzle extends through the nozzle housing and is attached to the nozzle housing base. The main stage fuel mixer has a plurality of inlets, each of which is adapted to receive a flow of gas, and an outlet adjacent to the main combustion zone. The main stage fuel mixer has a plurality of transition ducts, each associated with one inlet. Each transition duct provides fluid communication from the inlet associated with the transition duct to the outlet.

Proton spectroscopy without water suppression: the oversampled J-resolved experiment.

Abstract: A method is introduced for obtaining proton spectra in vivo with all the advantages of a full water signal. The method, based on F1 oversampled J-resolved spectroscopy, makes it possible to separate metabolite signals from unwanted baseline artifacts. The dominant water resonance is used as a 2D reference signal for the phase-sensitive reconstruction of the 2D J-resolved metabolite spectra. The powerful specificity of this method is demonstrated with model compound spectra, phantoms, and in vivo examples.

Simultaneous measurement of neutron and gamma-ray radiation levels from a TRIGA reactor core using silicon carbide semiconductor detectors

Abstract: The ability of a silicon carbide radiation detector to measure neutron and gamma radiation levels in a TRIGA reactor's mixed neutron/gamma field was demonstrated. Linear responses to epicadmium neutron fluence rate (up to 3/spl times/10/sup 7/ cm/sup -2/ s/sup -1/) and to gamma dose rate (0.6-234 krad-Si h/sup -1/) were obtained with the detector. Axial profiles of the reactor core's neutron and gamma-ray radiation levels were successfully generated through sequential measurements along the length of the core. The SiC detector shows a high level of precision for both neutrons and gamma rays in high-intensity radiation environments-1.9% for neutrons and better than 0.6% for gamma rays. These results indicate that SiC detectors are well suited for applications such as spent fuel monitoring where measurements in mixed neutron/gamma fields are desired.

Sintered electrode for solid oxide fuel cells

Abstract: A solid oxyde fuel cell electrode is produced by a sintering process. An underlayer (6) is applied to the electrolyte (4) of a solid oxide fuel cell in the form of a slurry, and dried. An overlayer (8) is applied to the underlayer (6) and dried. The dried underlayer (6) and overlayer (8) are then sintered to form a fuel electrode. The underlayer and the overlayer comprise a combination of electrode metal and stabilized zirconia with the overlayer comprising a greater percentage of electrode metal. The use of more stabilized zirconia in the underlayer provides good adhesion to the electrolyte, while the use of more electrode metal in the ovelayer provides good electrically conductivity. The sintered electrodes exhibit favorable performance characteristics, including good porosity, adhesion, electrical conductivity and freedom from degradation.

Study of creep behavior of ultra‐high‐molecular‐weight polyethylene systems

Abstract: The short- and long-term creep behaviors of ultra-high-molecular-weight polyethylene (UHMWPE) systems (compression-molded UHMWPE sheets and self-reinforced UHMWPE composites) have been investigated. The short-term (30-120 min) creep experiment was conducted at a load of 1 MPa and a temperature range of 37-62 degrees C. Based on short-term creep data, the long-term creep behavior of UHMWPE systems at 1 MPa and 37 degrees C was predicted using time-temperature superposition and analytical formulas. Compared to actual long-term creep experiments of up to 110 days, the predicted creep values were found to well describe the creep properties of the materials. The creep behaviors of the UHMWPE systems were then evaluated for a creep time of longer than 10 years, and it was found that most creep deformation occurs in the early periods. The shift factors associated with time-temperature superposition were found to increase with increasing temperature, as per the Arrhenius equation. The effects of temperature, materials, and load on the shift factors could be explained by the classical free volume theory.

Modular design and manufacture of a stator core

Abstract: An improved stator core and process for manufacturing the core are accomplished by a modular stator core design. The stator core is comprised of a series of equally sized and shaped stator core modules that are manufactured via a vacuum pressure impregnation process. The prefabricated modules can then be assembled into a stator core in an efficient way, saving several days of stator core assembly time. Moreover, a variety of stator core lengths can be accommodated by only inserting the required number of modules into the stator frame.

Blade group with pinned root

Abstract: A plurality of rotatable turbine blades are formed integral with a shroud and platform and a plurality of arcuate plate root portions which are received by circumferential grooves in a rotor and are fastened to the rotor by three pins extending axially through the root portions and the rotor, the shroud and platform portions having a protrusion on one corner to support the trailing edge of one of the blade portions and a notch in the shroud and the platform on the corner opposite the protrusion whereby the protrusions on one group of blades register with the notch on an adjacent group of blades when the groups of blades are disposed in a circular array on the rotor.

Combustor with two stage primary fuel assembly

Abstract: A combustor for a gas turbine having first and second passages for pre-mixing primary fuel and air supplied to a primary combustion zone. The flow of fuel to the first and second pre-mixing passages is separately regulated using a single annular fuel distribution ring having first and second row of fuel discharge ports. The interior portion of the fuel distribution ring is divided by a baffle into first and second fuel distribution manifolds and is located upstream of the inlets to the two pre-mixing passages. The annular fuel distribution ring is supplied with fuel by an annular fuel supply manifold, the interior portion of which is divided by a baffle into first and second fuel supply manifolds. A first flow of fuel is regulated by a first control valve and directed to the first fuel supply manifold, from which the fuel is distributed to first fuel supply tubes that direct it to the first fuel distribution manifold. From the first fuel distribution manifold, the first flow of fuel is distributed to the first row of fuel discharge ports, which direct it into the first pre-mixing passage. A second flow of fuel is regulated by a second control valve and directed to the second fuel supply manifold, from which the fuel is distributed to second fuel supply tubes that direct it to the second fuel distribution manifold. From the second fuel distribution manifold, the second flow of fuel is distributed to the second row of fuel discharge ports, which direct it into the second pre-mixing passage.

Combustion turbine with fuel heating system

Abstract: The combustion turbine system comprises a fuel line (50) connected to the combustor (30) with a portion of the fuel line being disposed in heat transfer relationship with the exhaust gas from the combustion turbine (28) so that the fuel may be heated by the exhaust gas prior to being introduced into the combustor. The sytem may also comprise a fuel by-pass (62) control system for mixing unheated fuel with the heated fuel to control the temperature (66) of the fuel being introduced into the combustor.

The role of custom power products in enhancing power quality at industrial facilities

Abstract: New technologies, using power electronics-based concepts, have been developed to provide protection for commercial and industrial customers from power quality problems on the electrical distribution system. Known as custom power products, the technologies described in this paper provide protection against sags, swells, voltage flicker, harmonics, and other power quality concerns. The custom power products can increase the availability of sensitive load and reduce costs associated with process interruptions. This paper covers two custom power products that were developed by Westinghouse Electric Corporation under contract to the Electric Power Research Institute (EPRI). The dynamic voltage restorer (DVR), which is a series-connected power electronics based device, quickly compensates for power system sags and swells. The distribution static compensator (DSTATCOM), which is a shunt-connected power electronics-based device, protects the electrical system from a polluting (flicker-producing) load. The DSTATCOM can be used in place of a traditional static VAr compensator and offers many advantages.

A.A.R. compliant electronic braking system

Abstract: A system reliably communicates brake commands from a master controller on a lead locomotive to the brake equipment on each rail vehicle of a freight train. The system includes a mechanism for detecting whether the brake commands are being successfully communicated over a communications channel that is normally used to convey such commands from the master controller to the brake equipment on each rail vehicle. The system also includes on each rail vehicle a mechanism for communicating the brake commands that is independent of the communications channel. The mechanism for communicating conveys the brake commands from the lead locomotive to the rail vehicles only when the mechanism for detecting determines that communication over the communications channel has failed. The system further includes on each rail vehicle a mechanism for receiving the brake commands from the lead locomotive via the mechanism for communicating. The system additionally includes on each rail vehicle a mechanism for acting upon the brake commands received from the mechanism for receiving so that the brake equipment can execute the brake commands as if they were conveyed to the brake equipment over the communications channel.

Automated in situ testing of railroad telemetry radios

Abstract: Railroad telemetry radios are tested by an automated method for in situ testing, so that only those units requiring adjustment and maintenance are removed. A multi-function test set is programmed to automate testing of the radios used in a telemetry system in conjunction with other test software embedded in the host telemetry devices. The radios contain both a transmitter and a receiver. Both are individually tested to verify proper performance. Receiver sensitivity testing of the radio is tested by bit error rate (BER) measurement with test software and a dedicated BER modulator. A known low amplitude message comprised of a short pseudorandom pattern continuously repeated by the test set BER modulator is demodulated by the radio receiver. The test software processes the received data and counts the number of errorless messages received over a specific period of time. The receiver sensitivity is known to be acceptable if the number of correct messages received is higher than a predetermined minimum value. The transmitter performance is tested by measuring radio frequency (RF) carrier frequency, modulation frequency, deviation and RF output power. The test set is programmed to automatically measure these parameters, determine whether they meet minimum requirements, prompt the technician as to pass/fail status, and optionally display measured test data for use in radio repair, if required, or for statistical purposes.

Sas fitting for tube and pipe connections

Abstract: The present invention provides an apparatus for making a tube connection. The apparatus comprises a sleeve having an interior surface adapted for receiving a tube section therein. The sleeve further has an exterior surface having a locking mechanism disposed on an outer portion thereon, such outer portion has a first end and a second end. There is an upwardly inclined surface extending from such second end of such outer portion of the sleeve. Extending inwardly from the upwardly inclined surface is a generally cylindrical sleeve wall that is substantially parallel to a longitudinal axis extending through the sleeve from one end to another. There is further a stop flange disposed on a center portion of such sleeve extending radially outwardly from such center portion of such sleeve, such stop flange is disposed substantially adjacent such generally cylindrical sleeve wall. Such apparatus further includes a driver mechanism for engaging and deforming the sleeve and concurrently such tube section engaged within the sleeve. The driver mechanism has at least two cylindrical sections for engaging the exterior surface of the sleeve. A first end of the driver contacts such stop flange of the center portion of the sleeve and a second end engages the locking mechanism of the outer portion of the sleeve. Such sleeve also includes an anti-torque surface treatment on the inner surface of the ends to resist torsion of the tube.

Railway locomotive ECP train line control

Abstract: An interface adapter is provided between the locomotive MU cable and the ECP trainline permitting ECP data from the lead locomotive to be transmitted via the MU cable on trailing locomotives to a train of ECP cars. On the lead locomotive, the HEU Echelon interface is on a suitable line in the MU cable instead of the separate ECP trainline such that trailing locomotives do not require a separate ECP trainline. The adapter generally employs two transceivers configured as back-to-back repeaters to bridge ECP data between the locomotive MU cable and the ECP trainline. A DC-DC converter can be used to provide the ECP trainline voltage, either as 230 VDC or as a lower voltage. In lower voltage systems the converter may be replaced by a voltage regulator, or may be eliminated. In any case, an inductor is employed on the output to provide a high impedance to the overlay transceiver.

Low Nox combustor having dual fuel injection system

Abstract: A dual fuel injection system for a low Nox combustor in which separate gaseous and liquid fuel manifolds are integrally joined to form manifold assemblies. Each manifold assembly extends circumferentially around the inlet of an annular fuel and air mixing passage. The gaseous fuel manifolds have a number of gas discharge ports spaced around their circumferences. The liquid fuel manifolds have a number of fuel nozzles spaced around their circumferences. The gaseous fuel discharge ports and liquid fuel nozzles are oriented so as to inject fuel into the annular passages in a manner that will facilitate mixing of the fuel and air. Separate gaseous and liquid fuel supply tubes are connected to each manifold.