Home > Blog > Subsea Cable Protection Systems, Damage Prevention & Fixed WTG | Part 4 of 5

Subsea Cable Protection Systems, Damage Prevention & Fixed WTG | Part 4 of 5

Published 17 Sep 2019

Subsea Cable Protection Systems

♦ Republished by Chris Dodds 

with Kind Permission of Greg Campbell-Smith ((Director Sales and Business Development at First Subsea)

Subsea Cables

 

 

First Subsea is the world’s leading developer of subsea connection technology, supplying, installing and decommissioning.

Subsea power cables on offshore wind farms are typically protected by means of burial.

This is a well proven means of cable protection used in other offshore industries.

However, at either end of offshore wind array cables they transition from burial, up through the water and into the wind turbine foundation. This free spanning section of cable is susceptible to what can be substantial wave and current loads.

These loads introduce movement and bending into the subsea cable which, without cable protection, can lead to over-bending, over-tensioning, fatigue and abrasion damage.

This exposed subsea cable is traditionally ‘protected’ by means of a relatively expensive and complex proprietary Cable Protection System (CPS).

Our 4th Article on Subsea Cable Protection Systems looks at why we need them for fixed wind turbine generators (WTG).

When First Subsea enteredthe renewable market we wanted to ask the simple question – Do we need subsea cable protection at all?

We had seen that traditional Cable Protection System (CPS) utilised bend restrictors which are designed to prevent overbending of subsea cables and from our studies we identified this would not occur in most projects. Restrictors also introduced additional loading to the subsea power cable due to hydrodynamic drag and increased inertia.

This in fact increased the risk of cable damage and reduced the inherent cable fatigue life.

This led us to reasoning why put a restrictor based CPS on at all if it reduces your cable life?

What Do You Think?

The study did identify that subsea medium/high voltage power cables cannot be left unprotected.

There is still a risk of cable damage due to Fatigue where the cable exits the foundation interface and Abrasion and Foreign body impacts.

These risks should be mitigated with a CPS optimised to protect against these types of damages. An optimised CPS design using stiffening elements like Bend Stiffeners and tubes will reduce the risk of subsea cable damage, including fatigue over the life of the wind farm.

 

➡ If you would like a copy of the report, please contact Chris Dodds [email protected] 

Subsea Cable Repair Protection

LV, MV & HV CABLE JOINTING, EARTHING, SUBSTATION & ELECTRICAL EQPT

Thorne & Derrick are Specialist Distributors to the UK and international Offshore Wind & Renewable industry to provide safe and reliable LV HV Electrical Cable & Power Distribution Systems – we are highly customer responsive and absolutely committed to providing a world-class service.

We have an International Distribution Agreement with Nexans Power Accessories UK to supply their Heat Shrink and Cold Applied ranges of 11kV/33kV/66kV joints and terminations and Euromold brand of separable connectors.

Since 1985, we have established an international reputation based on Service, Integrity and Trust – contact us.

t: 0191 410 4292 | e: [email protected] | www.powerandcables.com

We provide expert technical support and supply from a multi-million pound stock holding:

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  • Cable Accessories – Lugs, Glands
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Further Reading: