220 kV Y-Frames presentation - TNB.COM · · 2012-10-31frames and tower aesthetic has ruled out...
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CASE STUDY 1 Presented by Kunjal Pathak, P.E; William Gundy, P.E, S.E
Transcript of 220 kV Y-Frames presentation - TNB.COM · · 2012-10-31frames and tower aesthetic has ruled out...
CASE STUDY
1Presented by Kunjal Pathak, P.E;
William Gundy, P.E, S.E
Project Outline
TRTP Segment 3B
-Approximately 10 miles of 230 kV Single Circuit Transmission Pole Structures2
Project Outline
Tower Aesthetics
-Minimize VisualImpacts
-The “Y” Shape
Seismic Analysis
Full Scale Testing
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Thomas & Betts-Y-Frame Designer/ Manufacturer
W.E.Gundy & Associates- Seismic Analysis
Burns & McDonnell-Owner’s agent to provide overallProject Coordination
PAR Electrical Contractors Inc.-Engineering,Procurement and Construction Services
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Main Components of the Y-frame
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Different types and loadingon the Y-Frames
GO 95 Heavy Loading
Conductor: Bundled LAPWING (1590kcmil ACSR 45X7)
MT1 (230kV Medium Tangent) Maximum Wind span- 1200 feet with 0
Degree line angle
Maximum Weight span- 1650 feet
MT2 (230kV Medium Angle) Maximum Wind span- 1100 feet with 5
Degree line angle
Maximum Weight span- 1650 feet
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Different types and loadingon the Y-Frames
HT2 (230kV Heavy Tangent) Maximum Wind span- 800 feet with 0
Degree line angle
Maximum Weight span- 1000 feet
2.2” Radial Ice
HT3 (230kV Heavy Tangent) Maximum Wind span- 1100 feet with 0
Degree line angle
Maximum Weight span- 1600 feet
2.2” Radial Ice
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Governing Loading Conditions for Medium TangentY-Frames
All wires up with 21 psf ultimate wind on Bare wires and 31.5psf ultimate wind on Structure
Longitudinal load equal to Transverse wire loads withLongitudinal wind on Structure
Both Ground wires and one or Two Phases up
All wires up except one Phase or Ground wire back or aheadspan down. Ultimate longitudinal pull of 24 kips at any onephase location. No wind but ½” radial ice on wire
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Governing Loading Conditions for Heavy Tangent Y-Frames
All wires up with 30 psf ultimate wind on Bare wires and 45 psf ultimatewind on Structure
All wires up with 2.2” radial ice on wires and 11.25 psf ultimate wind onwires and 16.5 psf wind on Structure.
38.25 kips of Ultimate Vertical load for HT2’s phase location59.70 kips of Ultimate Vertical load for HT3’s phase location
Longitudinal load equal to Transverse wire loads with Longitudinal windon Structure
Both Ground wires and one or Two Phases up
All wires up except one Phase or Ground wire back or ahead span down.Ultimate longitudinal pull of 40 kips at any one phase location. No wind.
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Configuration
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Heavy loading on the Y-frames and toweraesthetic has ruled outthe traditional Throughplated or Box type armconnections on top ofthe leg of the Y-Frame.
Transition Assemblymet both the loadingand aestheticrequirements.
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Climbing sloperequirementcombined withElectricalclearances placedlimitation of the Y-frame Armdiameter andinternal anglebetween bifurcationarms.
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Design & ManufacturingChallenges
Transition Assembly
Transition Assembly layout
Finite Element Analysisperformed to design the TransitionAssembly
Inverted Y shaped diaphragmplates to Inverted T shapeddiaphragm plates
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Design &ManufacturingChallenges
Transition Assembly
Solid diaphragm plates withoutany zinc drainage slots requiredTransition Assembly to beMetalized.
Manufacturing challengesrelated to handling of Transitionassembly on shop floor, Weld-ability and weld inspection insidethe transition assembly andMetalizing.
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Full Scale test was performed on two Y-Frames HT2-115’ - Tested on 1 st Sept. 2009 MT1- 135’ – Tested on 10th Sept. 2009
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Three governing loadingconditions were appliedon MT1 Y-Frame Longitudinal Loading Broken Phase Loading Transverse Loading with
Unbalanced Vertical loadson Phases
Two governing loadingconditions were appliedon HT1 Y-Frame Broken Phase Loading Transverse Loading with
Unbalanced Vertical loadson Phases
Loading Increments andhold time
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Deflections
1 2
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135 FT Y FRAME 70 FT Y FRAME
Computer Model Computer Model
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Computer CodeSAP2000 used fordynamic earthquakeanalysis
Computer Codedeveloped byComputer &Structures Inc.specifically forearthquake analysis ofcomplex structures.
For the particularmodels of this studyshell elements wereused.
The mass distributionof the models wasobtained by thetributary distributionof the mass density ofvarious shell elementsto the boundary nodesof those elements.
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Reference: IEEE-693-2005 RecommendedPractices for SeismicDesign ofSubstations
Based on the SCESpec. the HighSeismic 5% dampingcurve was used.
.5g PGA and 1.2 g @cg of equipment
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Dynamic Characteristicsof 135’ Y Frame.
Fundamental mode isapproximately .68 cpshorizontal X & Ydirection.
Dynamic Characteristicsof 70’ Y Frame.
Fundamental mode isapproximately 1.6 cpshorizontal X & Ydirection.
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STRESS RATIOS 135’ STRESS RATIOS 70’
Component Name Frame Type Maximum Stress
Ratio
7/16 ” TUBE SECTION SHELL .33
3/8 ” TUBE SECTION SHELL .33
Y JUNCTION 3/8 ”
TUBE SECTION
SHELL .28
5/16” TUBE SECTION SHELL .15
CROSS ARM 1/4 ”
TUBE SECTION
SHELL .05
TOP ARM 1/4 ” TUBE
SECTION
SHELL .34
3” BASE PLATE SHELL .56
2” LOWER FLANGE SHELL .60
2” UPPER FLANGE SHELL .36
2” Y JUNCTION
FLANGE
SHELL .31
1 3/4 ” UPPER
JUNCTION FLANGE
SHELL .27
2” Y JUNCTION PLATE SHELL .27
2” Y JUNCTION PLATE SHELL .19
Component Name Frame Type Maximum Stress
Ratio
Y JUNCTION 3/8 ”
TUBE SECTION
SHELL .27
5/16”TUBE SECTION SHELL .17
CROSS ARM 1/4 ”
TUBE SECTION
SHELL .05
TOP ARM 1/4 ” TUBE
SECTION
SHELL .38
2.5” BASE PLATE SHELL .47
2”LOWER FLANGE SHELL .39
2”UPPER FLANGE SHELL .39
2”Y JUNCTION
FLANGE
SHELL .31
2” Y JUNCTION PLATE SHELL .29
2” Y JUNCTION PLATE SHELL .19
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COMPUTED DEFLECTIONSVS
TEST DEFLECTIONS
COMPUTER MODEL&
TESTED STRUCTURE
LocationID
FEAModel
TestedStructure
802 & 3 97.0” 98.4”
861 & 5 44.6” 43.2”
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