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The challenge of choosing the right method for surveying power cables

The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

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Page 1: The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

The challenge of choosing the rightmethod for surveying power cables

Page 2: The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

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Submarine power cables

Hydro 16 09.11.2016 Rostock

Wind farm

Inter- array

export cable

Power supply

Islands

Offshore constructions

Inter country

NorGer

BritNed

Page 3: The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

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HVAC (high voltage alternating current) HVDC (high voltage direct current)

HVAC vs. HVDC

Hydro 16 09.11.2016 Rostock

Page 4: The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

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Gotland 1 1954, 98km NorNed 2015, 580km

HVDC cable

Hydro 16 09.11.2016 Rostock

Page 5: The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

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Anchor strikes, dragging

fishing equipment

Poor planning Erosion

2K Criterion

Burial of cables

Hydro 16 09.11.2016 Rostock

The burial of cables decreases the risk of external damage and furthermore fixes the cable to its

projected position.

Page 6: The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

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Passive Systems

Fixed baseline, triangulation

Range – Altimeter = Depth of burial (DOB)

Detection systems

Hydro 16 09.11.2016 Rostock

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Detection Systems

Hydro 16 09.11.2016 Rostock

Active Sytem

- Acoustics

- Pulse induction

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Detection Systems – Comparison Matrix

Hydro 16 09.11.2016 Rostock

HVAC HVAC HVDC HVDC widely easy toin operation out of service in operation out of service tested operate

Teledyne TSS 350tone detection

passive Optimal Ranging

Field Sense

tone detection passive

Teledyne TSS 440pulse Induction

active

Innovatum Smartrak 9gradiometer

passive

Pangeo SBIacoustic

active

System Technology

Page 9: The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

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Passive Systems assume a radial electric field.

Challenges

Hydro 16 09.11.2016 Rostock

Page 10: The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

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Passive Systems assume a radial electric field.

3-core cables behave comparable to 1 coreconductors

Challenges

Hydro 16 09.11.2016 Rostock

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Passive Systems assume a radial electrical field.

3-core cables behave comparable to 1 coreconductors

Electrical field is disturbed by seabed and seawater flow.

Challenges

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Passive Systems assume a radial electrical field.

3-core cables behave comparable to 1 coreconductors

Electrical field is disturbed by seabed and seawater flow.

2-core cable design is conflicting with the radial electrical field model

Challenges

Hydro 16 09.11.2016 Rostock

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Accuracy requirements of federal- or private clients are derived from cable tracking specs.

Vertical-, horizontal accuracy of tracking system itself

Multisensor system is involved:

- DGNSS

- USBL system

- Altimeter readings of seabed

- Tidal effects

- Pressure sensors

- Latency effects

Accuracy

Hydro 16 09.11.2016 Rostock

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Seabed difference as burial survey

Hydro 16 09.11.2016 Rostock

Epoch

Cable lay (by barge)Cable lay (by barge)

1st by survey vessel1st by survey vessel

2nd by survey vessel

2nd by survey vessel

3rd by survey vessel

3rd by survey vessel

Classic approach

cable location from laying bargecable location from laying barge

cable tracking surveycable tracking survey

cable tracking surveycable tracking survey

cable tracking surveycable tracking survey

Time consuming / higher costs

MBES seabed difference

Cable location from laying barge

+MBES

Cable location from laying barge

+MBES

cable tracking survey + MBEScable tracking survey + MBES

MBES differenceMBES difference

cable tracking surveycable tracking survey

Faster / possible cable impacts detectable

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Summary

Hydro 16 09.11.2016 Rostock

BoundaryConditions

Methods and their

Limitations

Tool Selection

Baseline or MBES difference

survey

Equipment Carrier

Data processing and review

Presentation of results

ReportCharts

Page 16: The challenge of choosing the right method for surveying power cables€¦ · The challenge of choosing the right method for surveying power cables. 2 Submarine power cables Hydro

Thank you for your attention

M.Sc. Oliver Anders

FUGRO OSAE GmbH, Bremen