Showing papers by "Westinghouse Electric published in 1995"

The unified power flow controller: a new approach to power transmission control

Abstract: This paper shows that the unified power flow controller (UPFC) is able to control both the transmitted real power and, independently, the reactive power flows at the sending- and the receiving-end of the transmission line. The unique capabilities of the UPFC in multiple line compensation are integrated into a generalized power flow controller that is able to maintain prescribed, and independently controllable, real power and reactive power flow in the line. The paper describes the basic concepts of the proposed generalized P and Q controller and compares it to the more conventional, but related power flow controllers, such as the thyristor-controlled series capacitor and thyristor-controlled phase angle regulator. The paper also presents results of computer simulations showing the performance of the UPFC under different system conditions. >

Development of a /spl plusmn/100 MVAr static condenser for voltage control of transmission systems

Abstract: The availability of high power gate-turn-off (GTO) thyristors has led to the development of controllable reactive power sources, using electronic switching power converters, for use in power transmission systems This new technology has resulted in equipment that is fundamentally different from the conventional thyristor-controlled static VAr compensator (SVC) The new equipment is called a static condenser (STATCON) because its steady state output characteristics are similar to those of the rotating synchronous condenser The paper describes the fundamental operating principles, functional characteristics and basic control approach of the STATCON, with particular reference to a /spl plusmn/100 MVAr prototype planned to be installed at the Tennessee Valley Authority (TVA) Sullivan substation, USA This installation will be the first demonstration of a STATCON under the EPRI flexible AC transmission systems (FACTS) program, and will be the largest installation of its type in the world >

High‐temperature ohmic contact to n‐type 6H‐SiC using nickel

Abstract: Specific contact resistances measured at elevated temperatures for Ni ohmic contacts to 6H-SiC were reported. The specific contact resistances were measured with the linear transmission line method at both room temperature and at 500 C and yielded values less than 5 x 10(exp -6) ohm sq cm at both temperatures. The trend shows a decreasing contact resistance at higher temperature. The annealed metal film is a nickel silicide with substantial mixing of C throughout the silicide layer.

Sub-sea pumping system and an associated method including pressure compensating arrangement for cooling and lubricating fluid

Abstract: A pressure compensator for a sub-sea pumping system for pumping an effluent from a deep-sea wellhead comprising a topside module, a sub-sea module, and an umbilical connection between the topside and sub-sea modules. Hydraulic fluid is circulated through the sub-sea module for cooling and lubricating the motor and the pump. The hydraulic cooling and lubricating fluid is preferably a single hydraulic fluid that is compatible with the effluent being pumped. The hydraulic fluid is circulated through a submerged pressure compensator which may include a bellows assembly. The pressure compensator is responsive to the pressure of the effluent being pumped and pressurizes the hydraulic cooling and lubricating fluid to a pressure above the pressure of the effluent. The pressure compensator also responds when the volume of hydraulic cooling and lubricating fluid in the system is reduced or increased, such as by leakage or thermal expansion, in order to maintain the pressure of the hydraulic fluid.

Hydrocarbon reforming catalyst material and configuration of the same

Abstract: A hydrocarbon reforming catalyst material comprising a catalyst support impregnated with catalyst is provided for reforming hydrocarbon fuel gases in an electrochemical generator. Elongated electrochemical cells convert the fuel to electrical power in the presence of an oxidant, after which the spent fuel is recirculated and combined with a fresh hydrocarbon feed fuel forming the reformable gas mixture which is fed to a reforming chamber containing a reforming catalyst material, where the reforming catalyst material includes discrete passageways integrally formed along the length of the catalyst support in the direction of reformable gas flow. The spent fuel and/or combusted exhaust gases discharged from the generator chamber transfer heat to the catalyst support, which in turn transfers heat to the reformable gas and to the catalyst, preferably via a number of discrete passageways disposed adjacent one another in the reforming catalyst support. The passageways can be slots extending inwardly from an outer surface of the support body, which slots are partly defined by an exterior confining wall. According to a preferred embodiment, the catalyst support is non-rigid, porous, fibrous alumina, wherein the fibers are substantially unsintered and compressible, and the reforming catalyst support is impregnated, at least in the discrete passageways with Ni and MgO, and has a number of internal slot passageways for reformable gas, the slot passageways being partly closed by a containing outer wall.

Mixing apparatus & method for an optical agglutination assay device

Abstract: An assay device for detecting the presence of analytes in an unknown sample includes a reaction system wherein resilient storage reservoirs containing reagents are fluidly connected to a track containing the sample. An actuation mechanism forces the reagent from each of the reservoirs into the track where the reagents mix together and with the sample. The mechanism produces a first flow rate and the mechanism is operable to reverse the pressure applied to the reservoirs to reverse the direction of flow of the fluids in the track for a predetermined period of time after which the flow is again reversed. The mechanism then reduces the force applied to allow a second flow rate less than the first flow rate so that reaction can occur whereby a determination may be made as to whether the target analyte is present in the sample.

Relationships among Number of Fish Species Sampled, Reach Length Surveyed, and Sampling Effort in South Carolina Coastal Plain Streams

Abstract: To accurately estimate the number of species in stream fish assemblages, the reach length that is sampled must be increased until species number approaches an asymptote. Sampling effort affects the proportion of the assemblage that is sampled at any point along a stream and hence the reach length at which the asymptote is attained. 1 assessed the relationships among sampling effort, reach length sampled, and asymptotic species number in small (mean, 4.5 m low-flow wetted width), relatively species-rich (maximum, 30 species), first- to third-order southeastern coastal plain streams. With seven electrofishing passes, which sampled an estimated 60–90% of the fish at most of the 25 sample sites, reach lengths of 235–555 m (equivalent to 35–158 stream widths) were needed to collect all species; higher ratios of reach length to stream width were needed in smaller streams. With one electrofishing pass, which sampled an estimated 20% of the fish, reach lengths needed to be increased by factors of 3–4 to ...

Fault detection circuit for sensing leakage currents between power source and chassis

Abstract: A fault detection circuit for detecting leakage currents between a DC power source and chassis of an automobile, includes a voltage sensor coupled to the DC power source, the voltage sensor including an analog reference and a chassis ground A differential amplifier is coupled to the voltage sensor and detects variations in the analog reference and the chassis ground A voltage comparator unit determines whether the variations detected in the differential amplifier is above a predetermined threshold value A built-in test circuit tests whether the fault detection circuit is operating correctly

A 3-D hybrid finite element/boundary element method for the unified radiation and scattering analysis of general infinite periodic arrays

Abstract: We present a rigorous frequency domain variational 3-D electromagnetic formulation for the general nonself-adjoint infinite periodic array problem. The hybrid method described combines the vector finite element and Floquet boundary element techniques. It is general in the sense that it is applicable to infinite periodic arrays of the open or aperture-types. It is thus effective for modeling both the scattering and radiation performance of diverse FSS, absorber, and phased-array structures. The technique accurately handles arbitrarily complicated 3-D geometries, lossy inhomogeneous media and internal as well as external excitations. These analyses can be applied to general skewed grids under arbitrary scan and polarization conditions. >

Gas turbine vane with a cooled inner shroud

Abstract: A gas turbine vane (17) having an inner shroud (26) that is cooled by a portion of the cooling air directed to a cavity (45) between two adjacent rows of discs (55, 56). A portion of the cooling air in the cavity flows through impingement plates (83, 84) and impinges on the inner (98) surface of the inner shroud (26). Another portion of the cooling air flows through a passage (88) in the leading edge (42) of the inner shroud that has a pin fin (89) array for enhanced cooling. The impingement plates form chambers that collect both the impingement air and the pin fin passage air and direct it through holes (92) in the trailing edge (43) of the inner shroud for cooling of the trailing edge. Longitudinal passages (93, 94) along the side of the inner shroud direct the cooling air from the pin fin passage to the trailing edge (43).

Conformal mapping and hexagonal nodal methods. II: Implementation in the ANC-H code

Abstract: The ANC-H code is the hexagonal geometry version of the Westinghouse three-dimensional advanced nodal code ANC. Together with PHOENIX-H, the hexagonal geometry version of the Westinghouse pressurized water reactor (PWR) lattice code PHOENIX-P, they provide the Westinghouse code package for designing VVER-type PWR cores of hexagonal geometry. The nodal theory of ANC-H is the net current nodal expansion method implemented with the technique of conformal mapping, which maps a hexagon to a rectangle while preserving the diffusion operator. The use of conformal mapping eliminates the root cause of singularities resulting from the conventional transverse integration. The intranode burnup gradient is accounted for by allowing spatially dependent nodal cross sections. The theory of ANC-H is qualified by benchmarking ANC-H against fine-mesh finite difference code solutions for a variety of benchmark problems. In all cases, the agreement has been excellent. The accuracy of ANC-H for hexagonal geometry cores is as good as ANC for Cartesian geometry cores.

Method and apparatus for sequentially staged combustion using a catalyst

Abstract: A low NOx generating combustor in which a first lean mixture of fuel and air is pre-heated by transferring heat from hot gas (41) discharging from the combustor. The pre-heated first fuel/air mixture is then catalyzed in a catalytic reactor (86) and then combusted so as to produce a hot gas having a temperature in excess of the ignition temperature of the fuel. Second and third lean mixtures of fuel (32) and air are then sequentially introduced into the hot gas, thereby raising their temperatures above the ignition temperature and causing homogeneous combustion of the second and third fuel air mixtures. This homogeneous combustion is enhanced by the presence of the free radicals created during the catalyzation of the first fuel/air mixture. In addition, the catalytic reactor acts as a pilot that imparts stability to the combustion of the lean second and third fuel/air mixtures.

Interferometric moving ground target imaging

Abstract: This paper describes an interferometric synthetic aperture radar (SAR) processing technique, interferometric moving target focusing (IMTF), which is capable of creating clutter suppressed moving ground target images. One-meter range resolution data has been processed and is presented. The potential benefit of a moving ground target imaging system, the IMTF processing approach, differences between IMTF and other moving ground target imaging techniques and attributes of the moving target imagery are discussed.

Railway braking apparatus

Abstract: Apparatus for indicating the condition of hand brakes on railway cars and for applying and releasing railway car parking or hand brakes automatically in response to predetermined conditions including movement of a train, wayside conditioning apparatus, wayside operating mechanism, a signal controlled by an operator and performance of predetermined railway operating procedures, such as completion of an air brake test procedure. The apparatus may respond to mechanical, electrical and electronic signals and may operate on pneumatic or electric power provided from the service air brake system of a train or from a source of power outside of such air brake system.

Gas turbine combustor with turbulence enhanced mixing fuel injectors

Abstract: A combustor for a gas turbine having primary and secondary combustion zones. The combustor has primary gas fuel spray pegs for supplying a lean mixture of gaseous fuel to the primary combustion zone via a first annular pre-mixing passage and secondary fuel spray bars for supplying a lean mixture of fuel to the secondary combustion zone via a second annular pre-mixing passage. The fuel spray bars are aerodynamically shaped and a row of fuel discharge ports are formed on opposing sides of the spray bar. A pair of mixing fins project outwardly from the spray bar sides. The fins create turbulence in the air flow that ensures adequate mixing of the fuel and air. The fins have sufficient height and are displaced sufficiently far from the fuel discharge ports so that although the turbulence has not dissipated by the time the air flow reaches the fuel discharge ports, the zone of recirculation located downstream from the fins does not extend to the fuel discharge ports. This ensures that the spray bars will not act as flame holders and cause combustion to occur prematurely within the pre-mixing passage.

Fuel cell powered propulsion system

Abstract: Apparatus for powering an electric motor (4) comprising a solid oxide fuel cell (SOFC) (8) having a controlled fuel input (22) and a controlled oxidizer input (24). This apparatus may be combined with a turbine (104) driven by the exhaust gases of the fuel cell (8). The turbine (104) drives a generator whose power output (102) supplements the fuel cell power output (96) to power the electric motor (4). The oxidizer may be compressed by a compressor (98) driven by the turbine (104). The electric motor (4) may be a DC unipolar motor with controlled field excitation current. A controller (40') may control the fuel input (90), the compressor oxidizer input (108) or the field excitation current.

Series compensator inserting real and reactive impedance into electric power system for damping power oscillations

Abstract: A series compensator (11) for damping power oscillations in an electric power transmission system (1) includes a switching power converter (13) which injects a voltage into the transmission line (5) having a phase angle relative to transmission line current which is controlled to provide reactive compensation and to inject virtual real impedance into the line. The switching power converter (13) is a dc to ac converter which is capable of injecting virtual real impedance into the transmission line by virtue of the fact that it has a power exchange device (27) connected to its dc terminals (29). Where the power exchange device (27') is a resistor (37), the switching power converter (13) is capable of absorbing real power during surges in power on the line (5). Alternatively, the power exchange device (27) is a storage device (31) such as a battery bank or a super conducting magnet, in which case the switching power converter (13) can provide both virtual positive and negative real impedance.

Transmission line power flow controller with unequal advancement and retardation of transmission angle

Abstract: A bias voltage vectorially added to the controllable voltage injected in series with the line voltage of a transmission line reduces the required MVA rating for a unified power flow controller (UPFC) in applications where the power in the transmission line only flows in a single direction, or where the range of the transmission angle is otherwise unequal about zero.

Online diagnostic system for rotating electrical apparatus

Abstract: An online system for diagnosing operability of a rotating electrical apparatus includes sensors producing electrical variables corresponding to operating conditions of the apparatus, data converters for converting the electrical variables to digital values, a comparator for comparing the values to corresponding predetermined baseline values of the apparatus and producing a corresponding comparison value, and a signalling mechanism for outputting signals related to a period of predicted operability of the apparatus whenever the comparison value exceeds a corresponding predetermined deadband value The operating conditions may be non-electrical operating conditions, such as a condition of a lubrication system or a bearing of the apparatus Alternatively, the sensors may sense electrical insulation non-thermal parameters during operation of the apparatus, in order to produce signals related to the operability of an insulator of the apparatus The system may have a local processor for performing the comparisons and signaling Alternatively, the system may include an intermediate data storage and communication mechanism for storing and communicating the sensed values to a remote processor The processor may also trend the values with respect to time and determine a derivative of a sensed value The apparatus may be a motor operating in a hazardous environment, such as a reactor coolant pump (RCP) motor operating in a nuclear containment vessel

Meandering grain boundaries in YBa2Cu3Oy bi‐crystal thin films

Abstract: Artificially induced [001] tilt grain boundaries in epitaxial YBa2Cu3Oy (YBCO) thin films were prepared by deposition onto SrTiO3 bi‐crystal substrates and subsequently examined by transmission electron microscopy and atomic force microscopy (AFM). It was found that the YBCO grain boundary deviated from the path defined by the underlying substrate boundary, with the ‘‘meandering’’ YBCO boundary only generally following the path defined by the boundary in the underlying substrate. The AFM studies suggest this ‘‘meandering’’ behavior is related to the nucleation and growth mechanisms of the film, and based on this, we were able to vary the magnitude of the meandering by changing the growth conditions. The implications of this meandering behavior are significant, suggesting potential variations in electrical behavior from point to point along these boundaries. This effect is likely to be exacerbated by reduced junction linewidths and may lead to inconsistent behavior in devices which utilize this type of boundary.

Dynamic power and voltage regulator for an ac transmission line

Abstract: Apparatus (9) for providing reactive compensation and positive real power compensation in an ac electric power transmission system (1), utilizes a solid state inverter (11) to inject a series compensation voltage into the transmission line at a controllable magnitude and a controllable phase angle between + or -90 electrical degrees relative to transmission line current. The positive real power needed by the inverter (11) is drawn from the transmission line (3) by a rectifier (19) shunt connected to the line (3).

Gas turbine blade with cooled platform

Abstract: A turbine blade (18) has a cooling air flow path specifically directed toward cooling the platform portion (46) of the blade root (44). Two cooling air passages (48, 49) are formed in the blade root platform just below its upper surface. Each passage (48, 49) extends radially outward fron an inlet that receives a flow of cooling air (32) and then extends axially along almost the entire length of the platform (46). Each passage (48, 49) also has an outlet (52, 53) formed in the downstream face (61) of the platform (46) that allows the cooling air (32) to exit the platform (46) and enter the hot gas flow path. The passages (48, 49) are formed in portions of the platform (46) that overhang the shank portion of root.

Package seal inspection system

Abstract: On-line inspection of opaque, translucent and transparent elastomer sealed flexible and semi-rigid package seals is provided. In the case of highly reflective opaque seals of various elastomers and colors, low incident angle structured side lighting is used to locate and define the seal and highlight defects within the sealed area. For transparent i.e. highly light transmissive seals, not only is the low incident structured side lighting utilized to define the seal area, but back lighting of the package and seal is provided in order to then locate and classify defects within the seal boundaries. Multiple video images of portions of the area containing the seal and portions of the remaining lidstock are generated by CCD type cameras in response to one or more sensors which detect the presence and proper positioning of the package moving along a conveyor for image acquisition. The images generated are fed to one or more image processors which perform a series of stored program operations which determines if the package is accepted, possibly accepted, or rejected based upon the quality of the seal area and the presence of any defects in the seal boundaries.

Electric induction motor and related method of cooling

Abstract: An electric vehicle motor and related method of cooling wherein coolant is provided to a coolant inlet of the motor housing, directed through a plurality of radial slots of a stator core that is encased within the housing, and exited from a coolant outlet of the motor housing. The radial slots house the stator conductor wires such that the coolant is forced to come in contact with all of the external surface of all of the stator wires.

Gas turbine blade having a cooled shroud

Abstract: A gas turbine blade having a shroud extending outwardly from the tip of the airfoil portion of the blade. The shroud is cooled by cooling air passages formed within it. A radial cooling air supply hole directs cooling air directly from the blade root through the airfoil and to the shroud. A plurality of cooling air passages extend from the supply hole and are disposed adjacent bearing surfaces along which the shroud contacts the shroud of an adjacent blade. One of these cooling air holes is formed in the portion of the shroud that projects from the convex surface of the airfoil and another one of the cooling air holes is formed in the portion of the shroud that projects from the concave surface of the airfoil. The cooling air holes extend to the edge of the shroud and discharge the cooling through an opening in the edge.

A combined cycle designed to achieve greater than 60 percent efficiency

Abstract: In cooperation with the US Department of Energy`s Morgantown Energy Technology Center, Westinghouse is working on Phase 2 of an 8-year Advanced Turbine Systems Program to develop the technologies required to provide a significant increase in natural gas-fired combined cycle power generation plant efficiency In this paper, the technologies required to yield an energy conversion efficiency greater than the Advanced Turbine Systems Program target value of 60% are discussed The goal of 60% efficiency is achievable through an improvement in operating process parameters for both the combustion turbine and steam turbine, raising the rotor inlet temperature to 2,600 F (1,427 C), incorporation of advanced cooling techniques in the combustion turbine expander, and utilization of other cycle enhancements obtainable through greater integration between the combustion turbine and steam turbine