Havard Engineering Inc.

Photo on the left is from an ice storm in the 1959-60 winter showing ice thickness on a conductor which is close to ground level due to the ice weight breaking the upper left tower arm.

The layout of stockbridge dampers used to control vibration on a very long inlet crossing is shown on the right.

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Analytical methods are used to assess unusual configurations, and to permit alternative designs to be compared.

Examples include:

• Determining clearances for galloping between adjacent conductors or skywires and plotting clearance ellipses or envelopes.

• Checking sags of individual suspension spans of a line section after adding detuning pendulums.

• Finding optimum dimensions for Stockbridge damper wave traps to control aeolian vibration of a long inlet crossing.

• Reduction of field strain gauge data to confirm effectiveness of dampers to suppress tower member vibration.

• Optimization of asymmetrical bretelle damper designs

• Determining optimum asymmetric placement of stockbridge dampers

• State of the art study of refurbishment of transmission lines.

• Prioritization of spans and lines for assessment and refurbishment.

• Optimization of spacer damper locations.

• State of the art study of spacer-dampers.

• Interphase spacer location optimization.

• Analysis of ice accretion on different diameter conductors.

• Collapse of bundle conductors under high current induced electromagnetic attraction.

• Torsional stability of bundle conductors.

• Assessing the stability of hinged horizontal vee insulated arm constructions under high winds.

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An analytically determined plot of the clearance ellipses for galloping on a span of a two circuit transmission line is shown on the far left using the traditional method. The clearance envelopes calculated using the new criterion based on analysis of films of galloping motions is shown on the near left.

An asymmetric arrangement of stockbridge dampers to optimize control of aeolian vibration is shown on the right.

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If you require assistance with analysis of unusual configurations of spans of conductors or towers, we are prepared to assist you. Just send us an e-mail and we will contact you promptly to discuss your problem.