Installation Point Research Articles

Proposal of Designed Wind Speed Evaluation Technique in WTG Installation Point By Using the Meteorological Model and CFD Model

Proposal of Designed Wind Speed Evaluation Technique in WTG Installation Point By Using the Meteorological Model and CFD Model

Social networking effect at “HiWEL” kiosks amongst children

PurposeThe purpose of this paper is to study the values of children using Minimally Invasive Education (MIE) kiosks and identify any changes in these values as a result of using the kiosks.Design/methodology/approachThe sample consists of 85 children residing at the Vivekananda Camp. There are 44 boys with an average age of 11.62 years and 41 girls with an average of 11.75 years. Average education level of these children is up to the 8th class. Girls generally stop going to school after the 8th class as they are expected to prepare for marriage. The evaluation is based on the 12 key universal values specified (for children between 8 and 14 years) by the Living Values Educational Program, which are: peace, respect, cooperation, freedom, happiness, honesty, humility, love, responsibility, simplicity, tolerance, and unity. A questionnaire based on the above values is developed. Originally, the questionnaire consisted of 30 situational‐based questions with multiple choices. In the present paper, values at two time points are studied. First time point is during August 2004, prior to kiosk installation and second time point after seven months of exposure to MIE kiosk (April 2005).FindingsThe results clearly indicate that there has been a shift in the importance given to values by children prior to the learning station and after working for seven months at the learning station. It is interesting to note a shift in the range itself. In August 2004, the range was between 41 percent (helping others) and 79 percent (honesty) and in April 2005 it is from 46 percent (helping others) to 82 percent (politeness). In other words, values have moved up or gained more importance in the lives of the children. Apart from honesty and tolerance where a dip in the post‐phase is found, no change is perceived in academic excellence (74 percent) and religion (66 percent). For the remaining six values, there has been an increase in how strongly children feel that existence of these values in the post‐phase (ambition, politeness, kindness, consideration, teamwork, and cooperation).Originality/valueYoung children can develop values through their own experiential behavior and modeling. The paper shows that learning at MIELS emerges as an ongoing process, embedded in the environment.

Discrete Frequency Tuning Active Filter for Power System Harmonics

Severe voltage distortion, due to power system harmonic resonance, has been reported in recent years. This issue becomes more significant in high penetration of a photovoltaic (PV) network. A conventional voltage detection active filter operates as similar conductance for all harmonic frequencies to resolve this problem whether in a fixed conductance command or in an automatic gain adjustment control. However, its filtering capability is impeded by the mismatch between the active filter and the radial line, and the voltage distortion may still be significant. This paper proposes a discrete frequency tuning active filter to suppress power system harmonics. The active filter operates as variable conductance for each individual harmonic frequency. Each harmonic conductance is dynamically adjusted according to the corresponding harmonic voltage distortion of the active filter installation point in response to increase or decrease of nonlinear loads, or variation of resonant frequency in the power system. The mismatching problem between the feeder impedance and the active filter can be avoided effectively. Therefore, harmonic voltage distortion can be maintained at an allowable level throughout the feeder with lower peak current and lower rms current of the active filter, and loads installed at various locations of the power system receive more uniform voltage waveform.

Proposal of Designed Wind Speed Evaluation Technique in WTG Installation Point By Using the Meteorological Model and RIAM-COMPACT® CFD Model

Proposal of Designed Wind Speed Evaluation Technique in WTG Installation Point By Using the Meteorological Model and RIAM-COMPACT® CFD Model

Experimental and computational failure analysis of drillstrings

Drillstring failure analysis in an Iranian oilfield is investigated in this paper. A database containing over 750 failures developed and some conclusions were made. Based on the gathered database, the effects of the depth and casing pipe installation points were examined. The failures were investigated by metallurgical examinations and computational approach using finite element method. The results show that the fatigue cracks produced by different type of drillstring vibrations were responsible for majority of failures. Moreover, dynamic post failure analyses were done to predict the critical rotary speeds and the response of drillstring components. The results have been found to agree well with the field experiences.

A Dynamic Tuning Method for Distributed Active Filter Systems

The dramatic growth of power electronics applications has led to serious harmonic pollutions in the power system. The phenomenon of harmonic resonance resulting in severe voltage distortion has been reported. Various suppression techniques have been proposed to resolve this problem. Single termination active filter, whether operating with a constant conductance command or an automatically tuned conductance command, fail to suppress the harmonic resonance effectively and the voltage distortion may still be severe along the radial line. This paper proposes a capacity tuning scheme for the distributed active filter systems (DAFS) to enhance the harmonic filtering performance. Based on the measured voltage THD at the installation point, the active filter can dynamically adjusts its filtering capacity to maintain the voltage THD at a desired level. The proposed strategy can be integrated with the droop control between the conductance command and volt-ampere consumption so that the harmonic filtering workload is evenly shared among various active filter units of the DAFS. The operation principle is explained in this paper and test results based on simulation and experiment are provided to validate the proposed tuning scheme.

Dynamic Properties of Hydraulic Lines for Fluid Power Transmission

Dynamic Properties of Hydraulic Lines for Fluid Power TransmissionThis paper presents the results of a hydraulic line dynamic properties analysis taking into account inertia of the fluid flowing in rigid and flexible lines, the compressibility effect for this fluid and the viscous friction effect. The following are described and analyzed: solution of the wave equation in the form binding four variables: pressure and flow rate at the line input, and pressure and flow rate and the line output; two of the above-mentioned variables should be regarded as independent (input) and the other two as dependent (output), the accuracy comparison of distributed parameters model to lumped parameters model with regard to applicability range in hydraulic systems analysis, pressure value at given installation points as a response to rapid valve closing (transient response) or to valve opening (fluid hammer effect). In these considerations the hydraulic line is regarded as a two-port with two inputs and two outputs with a definite transmittance matrix. Main considerations concern the variable resistance model. A general solution is given as a function of the Laplace operator. Adaptation of the hydraulic line model to the turbulent flow and to the flow through a line with elastic boundaries is given. Introducing appropriate simplifications into the variable resistance model, the constant resistance model and lossless line model is obtained.Also, general solutions for three different lump parameter models are presented. Accuracy of individual methods are compared with examples for selected systems.

A shot in the dark

Investigations of recent blackouts indicate that the root cause of almost all of these major power system disturbances is voltage collapse rather than the underfrequency conditions prevalent in the blackouts of the 1960s and 1970s. The operation of today's power system with generation frequently being remote from the load centers has made the power system very dependent on the utility transmission system. When transmission lines trip, voltage drops at the load center, whereas frequency may remain normal until a complete system collapse occurs. Utilities have begun to recognize this problem and are installing UVLS programs. Also the industrial customers that have in-house generation that operates in parallel with the utility need to recognize the problem. These industrial cogeneration customers should consider the use of undervoltage separation schemes in addition to their existing underfrequency schemes to address the voltage collapse scenario. This article proposes undervoltage separation logic schemes that can be easily installed within digital relays to enhance the security of an undervoltage separation to prevent false operation due to slow-clearing system faults. The article also indicates the required point of installation of these relays so that they properly measure system voltage.

Nacelle Chine Installation Based on Wind-Tunnel Test Using Efficient Global Optimization

Design exploration of a nacelle chine installation was carried out. The nacelle chine improves stall performance when deploying multi-element high-lift devices. This study proposes an efficient design process using a Kriging surrogate model to determine the nacelle chine installation point in wind-tunnel tests. The design exploration was conducted in a wind-tunnel using the JAXA high-lift aircraft model at the JAXA Large-scale Low-speed Wind Tunnel. The objective was to maximize the maximum lift. The chine installation points were designed on the engine nacelle in the axial and chord-wise direction, while the geometry of the chine was fixed. In the design process, efficient global optimization (EGO) which includes Kriging model and genetic algorithm (GA) was employed. This method makes it possible both to improve the accuracy of the response surface and to explore the global optimum efficiently. Detailed observations of flowfields using the Particle Image Velocimetry method confirmed the chine effect and design results.

Load-flow conditions for hvdc transmission in synchronous networks

The basic purpose for HVDC (high-voltage direct current) transmission is to transmit a determined value of electrical power from one electrical node to another. If there is an AC system in parallel to an HVDC transmission, the load flow via this parallel AC system can be controlled directly. Since HVDC systems offer possibilities to perform fast load-flow control, they can also be used for improving stability. In this paper load-flow calculations of a simplified network are presented. First a comparison between HVDC transmission operating in asynchronous resp. synchronous networks is shown. Synchronous network means that the HVDC transmission works in parallel to an AC system at the same voltage level. It is shown how voltage at the point of installation and how the load angle are influenced due to the synchronous operation. A special regard is drawn to the losses of the transmission. Conditions for minimum total losses are presented. Informer calculations loads are involved. It is shown how they influence the minimum total losses.

In-Flight GPS-Signal-Reception Anomalies of Helicopters

I T IS difficult to find appropriate installation points for global positioning system (GPS) antennas on helicopters, because structures such as rotors and engines that are located above the fuselage may degrade GPS positioning accuracy. Even for fixedwing airplanes that have no such obstacles on the fuselage, an inflight GPS antenna performance study has revealed that large bias errors can be caused by distortions in the GPS antenna pattern due to other antennas nearby [1]. The effects of such problems are not so great when GPS usage is limited to en-route navigation. However, they will be more significant in approach and landing with vertical guidance (APV) or precision approaches using a GPS satellite/ ground-based augmentation system (SBAS/GBAS), such as the Federal Aviation Administration’s GPS wide/local area augmentation system (WAAS/LAAS). Although the minimum operational performance standards (MOPS) for WAAS/LAAS airborne equipment [2,3] specify an airborne accuracy model that includes an airframemultipath based on flight test data from large commercial jet transports [4], there is little quantitative flight test data for helicopter GPS antenna performance, and it is thought to be difficult for helicopters to meet the MOPS specifications. This paper presents in-flight GPS-signal-reception anomalies, such as GPS signal masking and multipath that degrade positioning accuracy, observed using the Japan Aerospace Exploration Agency’s (JAXA) research helicopter.

Industrial engineering studies for the manufacture of the ITER PF coils

Industrial studies have been carried out in Europe to prepare the manufacture of the five poloidal field (PF) coils, which will be manufactured on the ITER site. A first study, carried out by Ansaldo Superconduttori, addressed the manufacturing sequence, assuming the manufacture of the PF coils inside the two buildings which will further host the cryogenic system. A second study, carried out by Alstom investigated how to achieve the manufacture of some crucial points. A new layout of the manufacturing line was proposed, aiming at manufacture of the PF2–6 coils within 36 months. A recent study performed by Alstom, assumes the manufacture of the PF coils in a single dedicated building, releasing so the constraint of meeting the deadline fixed in ITER reference scheme by the starting point of installation of the cryogenic components.

Unified Power Quality Conditioner for Compensating Voltage Interruption

This paper proposes a new configuration for the Unified Power Quality Conditioner, which has a DC/DC converter with super-capacitors for energy storage. The proposed UPQC can compensate the reactive power, harmonic current, voltage sag and swell, voltage imbalance, and voltage interruption. The performance of the proposed system was analyzed through simulations with PSCAD/EMTDC software. The feasibility of system implementation is confirmed through experimental works with a prototype. The proposed UPQC has ultimate capability to improve the power quality at the point of installation on power distribution systems and industrial power systems.

New Configuration of UPQC for Medium-Voltage Application

This paper proposes a novel configuration of a unified power quality conditioner (UPQC) which can be connected to the distribution system without series injection transformers. The operation of the proposed system was analyzed through simulations with PSCAD/EMTDC and experimental works with a scaled hardware model, assuming that the UPQC is connected with the 22.9-kV distribution line. The proposed UPQC has the ultimate capability of improving power quality at the point of installation on power distribution systems. It has flexibility in expanding the operation voltage by increasing the number of H-bridge modules.

Combined Operation of Unified Power-Quality Conditioner With Distributed Generation

This paper describes analysis results of a combined operation of the unified power quality conditioner with the distributed generation. The proposed system consists of a series inverter, a shunt inverter, and a distributed generator connected in the dc link through a rectifier. The proposed system can compensate voltage sag and swell, voltage interruption, harmonics, and reactive power in both interconnected mode and islanding mode. The performance of proposed system was analyzed using simulations with power system computer aided design/electromagnetic transients dc analysis program, and experimental results with the hardware prototype. The proposed system can improve the power quality at the point of installation on power distribution systems or industrial power systems.

147 低周波大型構造物用2重動吸振器の設計法と応用(多自由度動吸振器による制振,OS-11 ダンピング(3))

The design methods of the optimum tuning and damping of the dual dynamic vibration absorber (D-DVA) for large-scale structures with very low frequencies were presented, arid the optimal construction layout which minimizes the undesirable moment applied to the base was examined. And then, for the both cases of displacement and force excitations, the approximate expressions for design parameters were proposed. Further, it was indicated that in the case of installing the D VA to the continuum structures subjected to the displacement excitation, the introduction of the new concept of the equivalent inertia mass in addition to the conventional equivalent mass and stiffness at the point of installation becomes necessary. Finally, by applying the present dual DVA to the vibration suppression of the first and the second vibration modes of a large-scale framework structure, the simulation results were obtained, showing the effectiveness of the present dual dynamic vibration absorber.

Effect of Reduced Reflective Wave Propagation on Overhead Contact Lines in Overlap Section

The vibration of overhead contact line caused by a patograph passing through an overlap section propagates on the overhead contact line and reflects at an anchor mast. The reflection wave thus generated returns to the pantograph and worsens the performance of current collection. To reduce the reflection wave with a damper, we used a model to calculate the constant and installation point for the damper, which were examined with a pantograph/catenary simulation program to prove that the installation of a damper decreased the contact loss ration and contact force fluctuations. This paper introduces the simulation that uses the results of theoretical calculation to reduce the reflection wave using a damper, evaluates the effectiveness of the damper from the viewpoint of contact loss ratio and contact force fluctuations.

On-Site Electromagnetic Compatibility of a Digital Wide-Range Neutron Monitor to Electric Fast Transients

All nuclear plant instrumentation connected at installation points to low-voltage power circuits will be exposed to electric fast transients induced by power switching and lightning. Unwarranted interruption of instrumentation due to transients may result in serious loss through bothersome activation of a plant’s engineering safeguards. In this study, in situ responses of a digital wide-range neutron monitor is studied in terms of real-time disturbances during electric transients. Using correlation analysis, a systematic methodology between transient responses and steady-state electromagnetic emission spectra has been developed and justified to be useful for transient isolation. Moreover, results of various on-site approaches to improve the electromagnetic compatibility of safety-related instrumentation are discussed.

Considerations of a shunt active filter based on voltage detection for installation on a long distribution feeder

This paper deals with a curious phenomenon referred to as the that may occur in a long-distance distribution feeder having many capacitors for power-factor correction. The idea of whack-a-mole is that installation of an active or passive filter on the feeder makes voltage harmonics increase on some buses, whereas it makes voltage harmonics decrease on other buses, especially at the point of installation. The distributed-parameter representation is applied to a simplified feeder, thus making it possible to perform analysis of the whack-a-mole. As a result, this analysis yields such a basic way as to avoid the whack-a-mole. Moreover, both theory and experiment clarify that installation of the active filter acting as a harmonic terminator on the end bus of the feeder can damp out harmonic propagation throughout the feeder without causing any whack-a-mole.

A shunt active filter based on voltage detection for harmonic termination of a radial power distribution line

This paper focuses on a shunt active filter based on the detection of voltages at the point of installation. The objective of the active filter is to attenuate propagation resulting from series/parallel resonance between capacitors for power factor correction and line inductors in a power distribution line. The active filter acts as a low resistor to the external circuit for frequencies, and it is installed on the end bus of the power distribution line, just like a 50 /spl Omega/ terminator installed on the end terminal of a signal transmission line. Therefore, the function of the active filter is referred to as harmonic in this paper. Experimental results obtained from a laboratory system rated at 200 V and 20 kW verify that the active filter for the purpose of termination has the capability of damping throughout the power distribution line.