Dynamic Interaction of High-Voltage Power Transformer Bushings, Turrets, and Tanks

2018 ◽  
Vol 34 (1) ◽  
pp. 397-421 ◽  
Author(s):  
Guo-Liang Ma ◽  
Qiang Xie ◽  
Andrew Whittaker
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Voltage ◽  
Power Transformer ◽  
Bending Moment ◽  
Dynamic Interaction ◽  
Electrical Performance ◽  
Element Analysis ◽  
Ground Shaking ◽  
Input Motion

High-voltage (HV) bushings are attached to a power transformer tank either directly or indirectly via turrets. Turrets are used to achieve electrical performance requirements, but their potential impact on the seismic performance of the supported bushings has not been considered. Earthquake simulator testing and finite-element analysis were used to quantify the amplification of ground shaking through tanks (220- and 500-kV) and turrets to the points of attachment of roof- and sidewall-supported bushings. Substantial amplification of motion was seen in both physical experiments and numerical simulations. Sample bracing schemes external to the transformer tank were investigated to potentially reduce the motions experienced by the bushings. Bushing tip displacements were reduced in all stiffening cases studied, but the outcomes for bending moment at the bushing-turret connection were mixed, with no change in some cases and significant reductions in others. The physical and numerical studies described in this paper make clear the importance of dynamic interaction of bushings, turrets, and the power transformer tank. The methods currently used to address the amplification of input motion from the base of a tank to the points of attachment of its bushing are inadequate. The seismic design of HV power transformer tanks and turrets should be supported by finite-element analysis of validated models to avoid dynamic interaction in the bushing-turret-tank system, to minimize seismic demand on the transformer bushings, and to minimize the risk of substation damage in earthquakes.

scholarly journals Modeling Stray Capacitances of High-Voltage Capacitive Dividers for Conventional Measurement Setups

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1262
Author(s):  
Alessandro Mingotti ◽  
Federica Costa ◽  
Lorenzo Peretto ◽  
Roberto Tinarelli ◽  
Paolo Mazza
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Equivalent Circuit ◽  
High Voltage ◽  
Equivalent Model ◽  
Simulation Environment ◽  
Element Analysis ◽  
Ratio Error ◽  
Complicated Geometries

Stray capacitances (SCs) are a serious issue in high-voltage (HV) applications. Their presence can alter the circuit or the operation of a device, resulting in wrong or even disastrous consequences. To this purpose, in this work, we describe the modeling of SCs in HV capacitive dividers. Such modeling does not rely on finite element analysis or complicated geometries; instead, it starts from an equivalent circuit of a conventional measurement setup described by the standard IEC 61869-11. Once the equivalent model including the SCs is found, closed expressions of the SCs are derived starting from the ratio error definition. Afterwards, they are validated in a simulation environment by implementing various circuit configurations. The results demonstrate the expressions applicability and effectiveness; hence, thanks to their simplicity, they can be implemented by system operators, researchers, and manufacturers avoiding the use of complicated methods and technologies.

scholarly journals A Review on Numerical Analysis of RC Flat Slabs Exposed to Fire

2020 ◽  
Vol 27 (1) ◽  
pp. 1-5
Author(s):  
Hanadi Naji ◽  
Nibras Khalid ◽  
Mutaz Medhlom
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Bending Moment ◽  
Mechanical And Thermal Properties ◽  
Vertical Deflection ◽  
Element Analysis ◽  
Flat Slabs ◽  
Numerical Studies ◽  
The Finite Element Analysis

This paper aims at presenting and discussing the numerical studies performed to estimate the mechanical and thermal behavior of RC flat slabs at elevated temperature and fire. The numerical analysis is carried out using finite element programs by developing models to simulate the performance of the buildings subjected to fire. The mechanical and thermal properties of the materials obtained from the experimental work are involved in the modeling that the outcomes will be more realistic. Many parameters related to fire resistance of the flat slabs have been studied and the finite element analysis results reveal that the width and thickness of the slab, the temperature gradient, the fire direction, the exposure duration and the thermal restraint are important factors that influence the vertical deflection, bending moment and force membrane of the flat slabs exposed to fire. However, the validation of the models is verified by comparing their results to the available experimental date. The finite element modeling contributes in saving cost and time consumed by experiments.

Capacity Analysis of PE Pipeline With Non-Planar Defect

2013 ◽  
Author(s):  
Weijie Jiang ◽  
Jianping Zhao ◽  
Dingyue Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Constitutive Model ◽  
Mechanical Performance ◽  
Orthogonal Design ◽  
Bending Moment ◽  
Limit Load ◽  
Capacity Analysis ◽  
Element Analysis ◽  
Load Factors

A tensile test of buried PE pipe is designed to test the mechanical performance. Then the constitutive model for the PE pipe can be established. The limit load of the PE pipe with local thinning defect can be studied with the method of combining the orthogonal design of experiment and finite element analysis. Then the factors of local thinning defect pipe limit load factors can be analyzed. The results show that the depth of the defect has a great effect on the limit load (internal pressure and bending moment) of PE pipe. The effects that the axial length of the defect and the circumferential length of the defect have on the limit load are not significant.

Vector Form Intrinsic Finite-Element Analysis for Train and Bridge Dynamic Interaction

2018 ◽  
Vol 23 (1) ◽  
pp. 04017126 ◽  
Author(s):  
Y. F. Duan ◽  
S. M. Wang ◽  
R. Z. Wang ◽  
C. Y. Wang ◽  
J. Y. Shih ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Interaction ◽  
Vector Form ◽  
Element Analysis

Finite Element Stress Analysis for Leak Tests of Pipe Flange Connections Subject to Internal Pressure and Bending Moment

2011 ◽  
Author(s):  
Satoshi Nagata ◽  
Toshiyuki Sawa ◽  
Takashi Kobayashi ◽  
Hirokazu Tsuji
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Bending Moment ◽  
Strain Gages ◽  
Element Analysis ◽  
Element Simulation ◽  
Sealing Performance ◽  
Gas Leak ◽  
Helium Gas

This paper reports the results of finite element analysis representing the sealing performance tests on the slip-on type pipe flange connections for 8 inch and 16 inch. The flange connections are subjected to internal pressure and bending moment. Internal pressure is applied by helium gas and the bending moment is loaded through 4 points bending equipment. Gas leak rates are measured by pressure decay method. During the test, the variations in the axial bolt force are monitored for all the bolts by strain gages. The pipe stress at the junction of pipe and flange is also measured. Finite element analysis simulates the tests and the simulated results are compared with the measured data. Then the behaviors of the slip-on type flange connections under internal pressure and bending moment as well as the sealing performance are clarified by the experiment and the finite element simulation.

Finite Element Analysis of <img src="/images/tex/20750.gif" alt="\hbox {Nb}_{3}\hbox {Sn}"> Sub-Cables Under Transverse Compression With Different Approaches

2013 ◽  
Vol 23 (3) ◽  
pp. 8400705-8400705 ◽  
Author(s):  
Tiening Wang ◽  
Luisa Chiesa ◽  
Makoto Takayasu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cross Sections ◽  
Load Distribution ◽  
Strain State ◽  
Transverse Load ◽  
Electrical Performance ◽  
Flat Plates ◽  
Element Analysis ◽  
Mechanical Loads

Currently, very few experimental results describing the behavior of Nb3Sn subcables under transverse load are available. Those results are of importance for predicting how a full-sized cable-in-conduit conductor behaves during operations. Current experimental devices used to study the effect of transverse load on the electrical performance of cables utilize concave plates to apply mechanical loads and contain the sample and subject it to mechanical loads that mimic the electromagnetic loads of full-sized cables during operation. From finite element analysis, it is found that the strain state in the strands of a triplet is greatly affected by the shape of the pressing element contact surface. We will discuss the strain state within the strands from the simulations using two pressing configurations: concave and flat plates. The strain state in each strand in a twisted triplet is investigated by considering two cross-sections of a triplet along the length of the cable. Those results can provide useful information on the electrical performance of each strand based on its location along the axis. It is verified that the load distribution is very different depending on the shape of the pressing plates.

An Improved Joint Model and Equations for Flexibility of Tubular Joints

1990 ◽  
Vol 112 (2) ◽  
pp. 157-168 ◽  
Author(s):  
Y. Ueda ◽  
S. M. H. Rashed ◽  
K. Nakacho
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bending Moment ◽  
Joint Model ◽  
Initial Stiffness ◽  
Element Analysis ◽  
Joint Flexibility ◽  
Elastic Plastic ◽  
Tubular Joints ◽  
Different Types

In tubular frames with simple joints, joints may show considerable flexibility in the elastic as well as the elastic-plastic ranges. Such flexibility may have large effects on the behavior of the structure as a whole. In a previous paper, an effective simple model of tubular joints is developed. The model takes account of joint flexibility in the elastic as well as the elastic-plastic ranges based on elastic-fully plastic load-displacement relatioships. In this paper an improved joint model is presented to provide better accuracy while maintaining simplicity. The accuracy of the model is confirmed through comparisons with results of finite element analysis. Equations to evaluate the initial stiffness of tubular T and Y-joints when braces are subjected to axial compression or in-plane bending moment are also presented. Such equations for different types of joints in different loading conditions are needed in order to avoid expensive calculations to evaluate the initial stiffness of joints.

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