scholarly journals Interdigital Capacitive Sensor for Cable Insulation Defect Detection: Three-Dimensional Modeling, Design, and Experimental Test

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Bing Luo ◽  
Tingting Wang ◽  
Fuzeng Zhang ◽  
Yibin Lin ◽  
Chaozhi Zheng ◽  
...  
Keyword(s):  
Electric Field ◽  
Power Systems ◽  
Three Dimensional ◽  
Capacitive Sensor ◽  
Element Model ◽  
Cable Insulation ◽  
Air Gaps ◽  
Insulation Defect ◽  
The Difference ◽  
Manufacturing Techniques

Due to excellent electrical and mechanical properties, cross-linked polyethylene (XLPE) cables are widely used in power systems. Poor manufacturing techniques in the production and installation of cable joints will cause insulation defects. The interdigital capacitive (IDC) sensor has advantages of simple structure and non-contact with the center conductor and shows great potential for online monitoring on XLPE cables. This paper focuses on the 3D modeling of a fully covered IDC sensor for cable insulation detection. Firstly, a 3D finite element model of the sensor is built, and the electric field distributions are compared with those of the partially covered sensor. For the sensor with more electrode pairs, the sensitivity increases with the sensor length and tends to saturate at the length of 5 cm, while the sensitivity remains constant for the sensor with fewer electrode pairs. Then, the differences between 3D and 2D results are discussed and the sensor parameters are optimized to reduce the influence of the fringe capacitance. The simulation results indicate that air gaps between the sensor and XLPE cable are the main reason of the difference between simulation and experiment. When the electrode width is equal to the gap width, the effects of both the fringing electric field and air gaps are relatively small. Finally, several types of sensors are made and used to detect the cable joint with and without the stress cone dislocation under different excitation voltage frequency. The results show that the measured capacitance decreases with frequency and the capacitance of the cable joint with the defects is smaller than that of the normal cable joint.

scholarly journals BEM Modelling of High Voltage ELF electric field applied to a 3D pregnant woman model

2010 ◽  
Vol 6 (1) ◽  
pp. 31 ◽  
Author(s):  
Cristina Peratta ◽  
Andres Peratta ◽  
Dragan Poljak
Keyword(s):  
Pregnant Woman ◽  
Electric Field ◽  
Electric Fields ◽  
High Voltage ◽  
Medical Information ◽  
Three Dimensional ◽  
Low Frequency ◽  
Element Model ◽  
The Body ◽  
Geometrical Properties

The paper introduces a three dimensional multidomainboundary element model of a pregnant woman and foetus for the analysis of exposure to high voltage extremely low frequency electric fields. The definition of the differentphysical and geometrical properties of the relevant tissues is established according to medical information available in existing literature. The model takes into account changes in geometry, body mass, body fat, and overall chemical composition in the body which influence the electrical properties, throughout the different gestational periods. The developed model is used to solve the case of exposure to overhead power transmission lines at different stages of pregnancy including weeks 8, 13, 26 and 38. The results obtained are in line with those published in the earlier works considering different approaches. In addition, a sensitivity analysis involving varying scenarios of conductivity, foetus postures and geometry for each stage is defined and solved. Finally, a correlation between the externally applied electric field and the current density inside the foetus is established and the zones of maximum exposure are identified.

The Forward Simulation of Tunnel Engineering Geological Exploration Based on Ansoft

2012 ◽  
Vol 459 ◽  
pp. 123-127
Author(s):  
Li Yao ◽  
Peng Fei Zhao ◽  
Hai Feng Zhao
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Induced Polarization ◽  
Simulation Software ◽  
Forward Simulation ◽  
Exciting Field ◽  
Response Characteristics ◽  
Geological Conditions ◽  
Geological Prediction ◽  
The Difference

This paper studies geology exploration problems of tunnel excavate process when geological conditions changed. The paper uses Beam test equipment based on AC induced polarization as a simulation model. Ansoft electric field simulation software is applied. It analyzes the electric field distribution of three-dimensional geological based on AC induced polarization, draws out potential diagram of the voltage distribution changing in geological conditions. When exciting field and geological conditions changed, the difference of exploration results is simulated. The geological prediction theory of Beam is better understood. Simulation results help to research the real-time detection of abnormal response characteristics and detection results of the interpretation.

scholarly journals Finite Element Analysis of Disc Insulator Type and Corona Ring Effect on Electric Field Distribution over 230-kV Insulator Strings

2012 ◽  
Vol 1 (4) ◽  
pp. 407 ◽  
Author(s):  
Ebrahim Akbari ◽  
Mohammad Mirzaie ◽  
Abolfazl Rahimnejad ◽  
Mohammad Bagher Asadpoor
Keyword(s):  
Finite Element ◽  
Electric Field ◽  
Power Systems ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Three Dimensional ◽  
Operation Time ◽  
Voltage Distribution ◽  
Element Analysis ◽  
Phase Conductors

Insulator strings are widely used in power systems for the dual task of mechanically supporting and electrically isolating the live phase conductors from the support tower. However, the electric field and voltage distribution of insulator string is uneven which may easily lead to corona, insulators surface deterioration and even flashover. So the calculation of the electric field and voltage distribution along them is a very important factor in the operation time. Besides, despite the variety of insulator material and profiles, no remarkable endeavor regarding their impacts upon electric field distribution has been made so far. In this paper, three-dimensional Finite Element Method (3-D FEM) softwareMaxwell is employed to simulate several 230-kV insulator strings with various types of porcelain and glass disc insulators and the electric field along them were compared, to investigate the effect of insulator types on electric field distribution.

Multi-Purpose Avionics Core Element: Using Digital Materials and Advanced Manufacturing to Rapidly Develop Cube Satellite Subsystems and Components

2013 ◽  
Author(s):  
Christopher Hartney ◽  
Elwood Agasid ◽  
Sarah Hovsepian
Keyword(s):  
Power Systems ◽  
Building Materials ◽  
Three Dimensional ◽  
Pilot Project ◽  
Advanced Manufacturing ◽  
Core Element ◽  
Peripheral Component Interconnect ◽  
Manufacturing Techniques ◽  
Manufacturing Technologies ◽  
The Cost

The NASA Ames Research Center (NASA Ames) Center Chief Technologist (CCT) Office sponsors the Advanced Digital Materials and Manufacturing for Space (ADMMS) Initiative, which focuses on advanced manufacturing technologies for space, including identifying several target products, areas and applications, approaches for advanced manufacturing, mechanisms for collaboration, and complementary facilities. The pilot project for this initiative is the Multi-Purpose Avionics Core Element (M-PACE). The primary goal of M-PACE is to demonstrate advanced manufacturing techniques, such as additive manufacturing and Digital Materials, to minimize the cost of cube satellites and increase their modularity. M-PACE will be designed and built at the NASA Ames’ SpaceShop, which is a state-of-the-art advanced manufacturing facility built for NASA researchers to formulate ideas for projects. The final products of M-PACE are several completed side panels of a one-unit (1U) (10 cm cube) cube satellite prototype built using commercial off-the-shelf (COTS) components, which will show the basic functionality of the internal payload by connecting it to the side panels for power and other subsystem capabilities. Within the structure, we are investigating the use of Digital Materials, which are universal building materials with the ability to increase precision and ease of assembly and disassembly of three dimensional (3D) objects. M-PACE will use COTS power systems and open-source hardware and software to distribute data through Ethernet through the use of snap-fit card connectors. Similar to Peripheral Component Interconnect (PCI) Express cards, we envision the spacecraft subsystems and payloads to be on a PC104-like board that will slide into the side panel connectors to enable distribution of power and data. This design has the potential to greatly reduce the cost of Cube Satellite testing and integration due to the absence of wires and ease of access to internal boards for any necessary modifications.

Three Dimensional Elastic-Plastic Finite Element Simulation on Bolt Tightening Beyond Yield

2009 ◽  
Author(s):  
Satoshi Nagata ◽  
Shinobu Kaneda ◽  
Hirokazu Tsuji ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Plastic Region ◽  
Three Dimensional ◽  
Element Model ◽  
Bearing Surface ◽  
3 Dimensional ◽  
Elastic Plastic ◽  
Element Simulation ◽  
The Difference

This paper presents 3-dimensional elastic-plastic finite element stress analysis simulating the behaviors of bolt and nut during the tightening process beyond the bolt yield so called plastic region tightening. The finite element model has the shape of helical threads as it is shown in the actual M16 stud bolt and heavy hex nut. The stress analysis is solved as contact problem among the engaged threads and the nut bearing surface to the clamped body. Tightening torque, thread torque, bearing surface torque and bolt axial force are calculated. They are compared with the experimental test results and show a fairly good agreement. Stress distribution as well as the development of plastic zone in the bolt and nut during the tightening are also demonstrated by this simulation. In addition, the load distribution in the engaged threads are computed and clarified the difference from those based on elastic analysis.

scholarly journals Investigation of Influence Factors of Wind-Induced Buffeting Response of a Six-Tower Cable-Stayed Bridge

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Zhi-Qiang Zhang ◽  
You-Liang Ding ◽  
Fang-Fang Geng
Keyword(s):  
Bridge Deck ◽  
Three Dimensional ◽  
Influence Factors ◽  
Element Model ◽  
Buffeting Response ◽  
Cable Stayed Bridge ◽  
Longitudinal Stiffness ◽  
Dimensional Finite Element ◽  
The Difference ◽  
Three Dimensional Finite Element

This paper presents an investigation of the wind-induced buffeting responses of the Jiashao Bridge, the longest multispan cable-stayed bridge in the world. A three-dimensional finite element model for the Jiashao Bridge is established using the commercial software package ANSYS and a 3D fluctuating wind field is simulated for both bridge deck and towers. A time-domain procedure for analyzing buffeting responses of the bridge is implemented in ANSYS with the aeroelastic effect included. The characteristics of buffeting responses of the six-tower cable-stayed bridge are studied in some detail, focusing on the effects including the difference in the longitudinal stiffness between the side towers and central towers, partially longitudinal constraints between the bridge deck and part of bridge towers, self-excited aerodynamic forces, and the rigid hinge installed in the middle of the bridge deck. The analytical results can provide valuable references for wind-resistant design of multispan cable-stayed bridges in the future.

Defocus ramp correction in spot-scan imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 130-131
Author(s):  
Kenneth H. Downing
Keyword(s):  
Computer Control ◽  
Three Dimensional ◽  
Sufficient Accuracy ◽  
Objective Lens ◽  
Electron Crystallography ◽  
Contrast Transfer Function ◽  
Tilt Axis ◽  
Specimen Height ◽  
The Difference ◽  
Envelope Functions

Three-dimensional structures of a number of samples have been determined by electron crystallography. The procedures used in this work include recording images of fairly large areas of a specimen at high tilt angles. There is then a large defocus ramp across the image, and parts of the image are far out of focus. In the regions where the defocus is large, the contrast transfer function (CTF) varies rapidly across the image, especially at high resolution. Not only is the CTF then difficult to determine with sufficient accuracy to correct properly, but the image contrast is reduced by envelope functions which tend toward a low value at high defocus.We have combined computer control of the electron microscope with spot-scan imaging in order to eliminate most of the defocus ramp and its effects in the images of tilted specimens. In recording the spot-scan image, the beam is scanned along rows that are parallel to the tilt axis, so that along each row of spots the focus is constant. Between scan rows, the objective lens current is changed to correct for the difference in specimen height from one scan to the next.

The Effect of Roughness Features on Mos Surface Electric Field and Fowler-Nordheim Tunneling Behavior

1997 ◽  
Vol 473 ◽  
Author(s):  
Heng-Chih Lin ◽  
Edwin C. Kan ◽  
Toshiaki Yamanaka ◽  
Simon J. Fang ◽  
Kwame N. Eason ◽  
...  
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Tunneling Current ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Interface Roughness ◽  
Normal Electric Field ◽  
Surface Electric Field ◽  
Tunneling Behavior ◽  
Nordheim Tunneling

ABSTRACTFor future CMOS GSI technology, Si/SiO2 interface micro-roughness becomes a non-negligible problem. Interface roughness causes fluctuations of the surface normal electric field, which, in turn, change the gate oxide Fowler-Nordheim tunneling behavior. In this research, we used a simple two-spheres model and a three-dimensional Laplace solver to simulate the electric field and the tunneling current in the oxide region. Our results show that both quantities are strong functions of roughness spatial wavelength, associated amplitude, and oxide thickness. We found that RMS roughness itself cannot fully characterize surface roughness and that roughness has a larger effect for thicker oxide in terms of surface electric field and tunneling behavior.

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