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THE 4D SERIES VIBRATION
DAMPERS
| WE TOOK THE VERY BEST DAMPER DESIGN IN
THE WORLD AND MADE IT BETTER |
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WHAT THE INDEPENDENT CRITICS
THINK...
Once we developed what
we believe to be the best vibration damper in the world, we asked
the toughest independent laboratories in the world to put us through
our pages. The Queensland University, Georgia Power Research Centre,
and, the Elect Power Research Institute of Beijing, conducted
various tests in accordance with IEEE Draft Standard 664 Revision
6th April, 1993. Australian Standard AS1154 and Pacific Power's own
stringent specification. These included impedance measurement, power
dissipation and inverse standing wave ratio-ISWR. This is how we
looked:
Southern Electric International Inc.(Georgia Power
Research Centre)
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DYNAMIC
CHARACTERISTICS
FOR 0.05 m/s CLAMP
VELOCITY |
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DYNAMIC
CHARACTERISTICS
FOR 0.01 m/s CLAMP
VELOCITY |
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Dynamic characteristics
data were scaled and plotted using a Lotus spreadsheet. To obtain
the greatest resolution for all parameters, power is scaled directly
in watt,s force is scaled in Newtons divided by 10, and phase
displayed as cosine (phase). Figures 1 and 2 are the dynamic
characteristics of the damper for 0.05 m/s and 0.1 m/s velocity
respectively.
Conclusion. The prototype 4D30 damper has
resonances at 8,
14, 28 and 51Hz. The frequency range of concern for "Lemon"
conductor is 9Hz to 60Hz, which is well covered by this damper. The
shape of the response curve obtained from a shaker table is not the
same as a test curve from a test span. However, certain
characteristics predict if a damper will work well on a span test:
proper coverage of the required frequency range, and freedom of
extreme peaks and valleys in the response curve. Excessive peaks and
valleys are generally caused by loosely wound messenger cables,
which cause sharp resonances in the damper response. The prototype
damper submitted for testing has the proper dynamic characteristics,
and has met performance requirements as per figures 3 and 4 when
tested on a laboratory span.
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ISWR
PERFORMANCE Vs. BPA EFFIENCY CURVE
SAMPLE DL 9310, 21mm DIAMETER
CONDUCTOR |
IMPEDANCE
CHARACTERISTICS - BEFORE & AFTER
SAMPLE DL 9310, 4D30 FATIGUE TEST 107
CYCLES |
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The University of
Queensland(Department of Mechanical Engineering)
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ISWR
PERFORMANCE Vs. BPA EFFIENCY CURVE
SAMPLE DL 9304, 29.3mm DIAMETER
CONDUCTOR |
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Calculations of ISWR
for the 4D40 damper, DL9304 are enclosed. The calculations were made
for both Mango and Orange conductors, and Damper distance
1.0m.
 The HARO asymmetric vibration
damper, developed by Laurie Haro and Tapani Seppa of Imatran Vioma
in 1967 was the first improvement on the original Monroe and Templin
"Stockbridge" damper. Made specifically for the
Saskatchewan Power Corporation it solved their problems of high
frequency vibration on the flat terrain of the Squaw Rapids to
Beatty 230kV line.
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DAMPER
EFFICIENCY
Phillips Fitel OPGW -
11.6MM dia. |
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Subsequent developments
by Claren and Diana and other researchers simplified and refined the
Haro asymmetric principle culminating in the current Dulhunty 4D
design.Up to this time, stockbridge dampers had only two resonant
modes covering just two frequencies.The new Dulhunty 4D series,
incorporating an ultra sensitive energy absorbing hand made
"messenger" cable is capable of responding to and absorbing the
energy of conductors vibrating at 6Hz to 150Hz with four basic
resonant modes. These modes interact to provide a flat frequency
response. In simple terms the DULHUNTY 4D range of vibration dampers
offers complete vibration protection for all cables, from 6mm dia.
earthwires and OPGW to 45mm dia ACSR or AAAC. Just five sizes are
made to cover this range.Technical literature and specialist advice
is available at all times from personnel who have specialised in
this area for over half a century.Type tests, sample tests and
routine tests are an ongoing procedure at Dulhunty Industries /
Australian Defence Industries' Test and Certification Centre at St.
Marys NSW.Live Line field recordings on your own transmission lines
can be undertaken to assess vibration intensity and fine-tune
placement, frequency response, and energy balance and to confirm the
efficiency of the dampers installed.Aeolian vibration, its
assessment and control is a subject for experts - don't leave it to
your normal hardware and fittings supplier.
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Dulhunty
power | Manufacturing and
quality assurance
The Dulhunty group of
companies is pleased to advise that its Quality System is fully
accredited under AS3902/ISO9002 licensed by Australian Standards
QEC2822 and NQA UK. |
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