2018 rmel fiberglass crossarm program at xcel …...– xcel energy is working on a galloping...
TRANSCRIPT
Presented by David Flaten
2018 RMEL
F IBERGLASS CROSSARMPROGRAM AT XCEL ENERGY
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JUPITER STORM
• The storm severely damaged trees and power lines in the Texas Panhandle
• As much as 1 ½” of ice. Initially had strong winds
• Damage To Over 7,500 Structures– 1,350 power poles replaced– 2,300 cross-arms replaced– 6,000 insulators replaced– Over 9 miles of conductor
• A 73 mile portion of a 34.5kV line serving the communities of Higgins,Follett, Lipscomb, and Darrouzett was lost
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STRUCTURE DAMAGE
• Infrastructure Age –– Some assets new as two months old – Some are over 50 years old – Asset renewal can reduce but not eliminate failures from icing events
• Damage on both Grade C and Grade B construction – Cross arm Failure
• Ice loading in some areas added 500+ pounds per phase based off icing profiles
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FIBERGLASS CROSSARM DAMAGE
• Failures– Typical fiberglass crossarm damage from Jupiter Storm
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FIBERGLASS ARM FAILURES
• Arm pins failures– Had very heavy loads– Had high wind– Had lines that galloped
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FIBERGLASS ARM TESTING
• Attachment to pole– Fiberglass arm to metal pole bracket does not hold it immobile
• Holes will enlarge• Inserts might not be of much help
– Xcel Energy is working on a galloping certification test
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FIBERGLASS ARM TESTING
• Lead head Insulator Arm Pin– Insulator pin failed. Roughly 1,400 lb force, some crossarm damage
after the pin failed. – Nut was tightened very tight. (If it was loose would probably tear.)
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FIBERGLASS ARM TESTING
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FIBERGLASS ARM TESTING
• 35kV Porcelain Post– Don’t overtighten, can crack surface– 707 lb ultimate load with 2 ¼” x 2 ¼” flat washer– 4” x 4” washer – 1,204 lb test strength – 70% improvement
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FIBERGLASS ARM TESTING35KV POLYMER POST
• Light Series– 450 lb, - 2 ¼” washer– 4” x 4” bottom only – 452 lb, insulator side fails– 4” x 4” top and bottom – 698 lb, 54% increase in strength
• Stronger Series - 82% stronger arm model, • Wall thickness - .200→.270 H, .180→.240 V (Different composition)• 495 lb - 2 ¼” washer
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FIBERGLASS ARM TESTING
• Angle Pin – 35kV Polymer Post– Use ¾” bolt, 4” x 4” washer – Load 1,119 lb– Testing is ongoing for product improvements
• Blocking inside for better crush and failure resistance?
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WOOD CROSSARM TESTING
• Wood Arm– Wood has higher compressive strength– Tangent, 822 lb
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FIBERGLASS CROSSARMSPECIFICATION
Testing Requirements• Standard Tests
– Vertical – Horizontal– Transverse
• Test Positions– 2-point– 4-point
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FIBERGLASS CROSSARMSPECIFICATION
Testing Requirements• Dynamic Load Test
– Simulated galloping conditions• 5-30 revolutions per minute• Load to 50% of ultimate
strength• 8 hour duration, both
vertical and horizontal directions
– Results• Damage to arm• Hole enlargement• Loose hardware
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FIBERGLASS CROSSARMSPECIFICATION
Testing Requirements• Wall Crush Resistance
– Pounds of force, – 2¼” x 2¼”, standard washer
with pin. • Surface splitting, cracking and
tearing.– 4” x 4” washers, wall to all arm
coverage• Corner strength and side wall
performance
• Could be done as a push or a pull load
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FIBERGLASS CROSSARMSPECIFICATION
Testing Requirements• Crossarm Pin Transverse Load
– Standard 6” leadhead crossarmpin
– 2¼” x 2¼” washer• Test results
– Pin tear out– Wall, insert or hole damage– Loading 900 lbs
• Considerations– Tightening torque probably
makes a big difference– Washer size probably makes a
big difference
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FIBERGLASS CROSSARMSPECIFICATION
Testing Requirements• Post Insulator
– 35kV insulator test– Polymer or Porcelain– 4” x 4” washer – Angle pin
• Results– End collapse– Crushing or tear out
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FIBERGLASS CROSSARMSPECIFICATION
Testing Requirements• Torsional Loading
– Simulate non-equal loading– Span length differences– Ice drop
• Test setup– 45 degree load longitudinal on
post insulator