Cable Installation
The sub sea cables that will connect wind turbines to the offshore substation (collection
cables) and connect the wind farm to shore (transmission cables) must be protected in
order to prevent damage from anchors and other potential objects. This is generally
achieved by burying the cable to an appropriate depth and using cables with in-built
amour protection. In some cases, where anchor damage is believed to be a high risk,
additional protection above the cable may be desirable.
Jetting
The jetting method is expected to be used to install all the wind farm collection cables
and the majority of the transmission cable to depths of at least 3-5m. Jetting is a
technique that causes minimal disturbance and is well proven with many similar projects
in Hong Kong. Jetting works by using a high-pressure water jet to fluidise the seabed,
and then placing the cable so that it sinks under its own weight.
Electrical cable installation has been frequently practised in the HKSAR, with recent
studies having identified that potential disturbances from such minor works are likely to
be minimal, localised and of a short duration[1].
Jetting cables does not adversely affect fishing activities as the sea bed returns to its
previous form shortly after the cable embeds itself in the seabed.
Further Anchor Protection
Studies of anchor damage risk specifically conducted for the Project indicate that it will be
necessary to provide additional protection for 3km of the transmission cable in Tseung
Kwan O. This would be done through the use of jetting +concrete slabs or rock armour.
In the case of using rock amour dredging will be necessary, with the dredging rate not
expected to exceed 6,300 m3 per day. The total volume of dredged materials is expected
to be no more than a total of 135,000 m3. The impacts are considered further in the
water quality EIA section.
Both methods would be finished flush to the seabed.
--------------------------------------------------------------------------------
[1]EIA Submission DIR-143/2006 Proposed 132kV Submarine Cable Route for Airport "A" to Castle Peak
Power Station Cable Circuit, CLP Power. July 2006.
The sub sea cables that will connect wind turbines to the offshore substation (collection
cables) and connect the wind farm to shore (transmission cables) must be protected in
order to prevent damage from anchors and other potential objects. This is generally
achieved by burying the cable to an appropriate depth and using cables with in-built
amour protection. In some cases, where anchor damage is believed to be a high risk,
additional protection above the cable may be desirable.
Jetting
The jetting method is expected to be used to install all the wind farm collection cables
and the majority of the transmission cable to depths of at least 3-5m. Jetting is a
technique that causes minimal disturbance and is well proven with many similar projects
in Hong Kong. Jetting works by using a high-pressure water jet to fluidise the seabed,
and then placing the cable so that it sinks under its own weight.
Electrical cable installation has been frequently practised in the HKSAR, with recent
studies having identified that potential disturbances from such minor works are likely to
be minimal, localised and of a short duration[1].
Jetting cables does not adversely affect fishing activities as the sea bed returns to its
previous form shortly after the cable embeds itself in the seabed.
Further Anchor Protection
Studies of anchor damage risk specifically conducted for the Project indicate that it will be
necessary to provide additional protection for 3km of the transmission cable in Tseung
Kwan O. This would be done through the use of jetting +concrete slabs or rock armour.
In the case of using rock amour dredging will be necessary, with the dredging rate not
expected to exceed 6,300 m3 per day. The total volume of dredged materials is expected
to be no more than a total of 135,000 m3. The impacts are considered further in the
water quality EIA section.
Both methods would be finished flush to the seabed.
--------------------------------------------------------------------------------
[1]EIA Submission DIR-143/2006 Proposed 132kV Submarine Cable Route for Airport "A" to Castle Peak
Power Station Cable Circuit, CLP Power. July 2006.
Section of Cable Requiring Protection
Rock Armour
Concrete Slabs
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