Havard Engineering Inc. Web Page
Havard Engineering Inc. controlling vibration and galloping for the electric power supply
industry
Havard Engineering Inc.
David G. Havard, Ph.D., P.Eng.
Jana Havard, M.A.Sc., P.Eng.
E-mail: dhavard@rogers.com
Services Offered
Based on over 40 years experience with electrical power
utilities across the globe, Havard Engineering Inc. provides mechanical and civil engineering
services to users of overhead electric power lines.
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Also we have created two albums if you wish to see or download the full size images. You can reach
these by clicking on the thumbnails. More detailed information is available on each topic by clicking
on the heading.
These services include diagnosis and control of problems due to aeolian vibration of single
conductors which may become apparent through fatigue or wear of conductors, suspension
clamps, Stockbridge vibration dampers and even tower members.
A live line vibration recorder in use on an operating line to monitor conductor motions at an AGS clamp
is shown on the right.
Bundle conductors are susceptible to both aeolian vibration and wake induced oscillation.
When two, three, four or more subconductors are used vortex wakes from the leading subconductors impact
downstream subconductors and cause complex oscillation modes involving all subconductors in the
bundle. A typical spacer-damper used to control both of these wind-induced vibratory motions is shown
on the left.
Conductor Galloping
Galloping of conductors due to icing and wind action can be significantly reduced by the addition of
detuning pendulums designed specifically for the line section by Havard Engineering Inc., and
manufactured by associated companies.
Interphase spacers and detuning pendulums installed on a two-conductor bundle line for galloping
control are shown on the right.
Structural Testing
The application may require monitoring the vibration on the conductors or towers and/or mechanical
testing of worn or aged components. A tensile test of a strand of an aged ACSR conductor is shown on
the left.
Analysis of Special Problems
Analytical methods are used to evaluate alternative designs for special needs and arrangements.
Computer programs have been written and applied to simulate critical features of transmission line
behaviour,
such as determining the limits of stability of hinged horizontal vee insulated arm designs under high
winds.
An analytically determined plot of the clearance ellipses for galloping on a span of a two circuit
transmission line is shown on the immediate right using the traditional method.
The clearance envelopes calculated using the new criterion based on analysis of films
of galloping motions is shown on the far right.
Workshops and Courses
Open courses on overhead line vibration and assessment of
aged lines have been given in numerous locations in Asia, Europe, and North and South America. However, we no longer offer open courses. In-house courses can be arranged as described below.
In-house courses have been tailored to specific utility needs and presented to
technical staff at their workplace.
The topics covered include:
Assessment, of conductors, line components, hardware and structures
Upgrading and refurbishment of lines, foundations and structures
Conductor vibration, wake induced oscillation and galloping - measurement and control
Mechanical aspects of all types of fibre optic cables
Impact of the 1998 Canadian ice storm on overhead lines
Damage to structures due to wind induced vibration
Technical Contributions
Active Member and Past Convenor: CIGRE SC22 WG11 "Mechanical Aspects of Overhead Conductors".
Senior Life Member of IEEE, Towers, Poles and Conductors Subcommittee.
Active Member of IEEE Working Group on Conductors
Past Adjunct Professor, Mechanical Engineering Dep't, University of Toronto.
Technical Coordinator of CEA Interest Group on Transmission Line Asset Management (1999-2000)
Author of over 200 papers and presentations on mechanical problems on overhead power lines.
Just follow this link for a selection of technical papers presented
To contact us please send an e-mail to: dhavard@rogers.com
In-House Courses