October 30, 2023
It takes DLM’s full suite of state-of-the-art load cells, force measurement technology and cable working equipment to serve the wind energy sector, as Martin Halford, the company’s managing director, tells us.
Dynamic Load Monitoring (UK) Ltd. (DLM) has supplied load cells plus load monitoring and cable working equipment to the wind energy and wider renewables sector for a decade. It often partners with sister company, Vulcan Offshore Ltd., also of Southampton, UK, which is a specialist in fabrication, welding, and computer numerical control (CNC) machining.
Initially, DLM supplied running line monitors (or RLMs) and saddleback monitors; RLMs were first used in monitoring tension when pulling cable into offshore platforms. Saddlebacks, meanwhile, were employed to monitor the tension in cable being laid on the seabed, which is used to transfer power from wind turbines to the shore.
Martin Halford, managing director at DLM, recalls that the company also supplied a lot of its early telemetry load links and load pins, again, for monitoring the tension when pulling cable into offshore platforms and transmitting to both the vessel, where the cable is coming from, and the operators on the platform, ensuring that the cable was not overloaded, causing damage.
He adds, “The sector has become huge now; with governments’ net zero targets, the push for offshore wind, especially, has grown exponentially over the last 10 years. Today, approximately 65 to 70% of our turnover is related to subsea cable lay and offshore work—probably around 60% of that is related to offshore wind.”
Grappling with demand
With an abundance of installed wind infrastructure in the UK, and places such as Taiwan and the U.S., gathering pace lower down the growth curve, wind is inescapably a global market that requires a full suite of hardware, supporting software, and expertise from DLM. Grapnels, subsea load pins, telemetry shackle load cells, telemetry tensile links, saddleback monitors, and RLMs are ordered daily. A single (hire or purchase) contract can include products ranging from 5t to 80t capacity.
Grapnel trains are systems consisting of multiple grapnels attached to a wire; they are used to grapple for cables that either need to be recovered to the deck of a vessel to be repaired, or removed as they are no longer in service. Grapnels are used in a train arrangement and towed along the seabed during pre-lay grapnel run (PLGR) and route clearance operations.
This work is conducted prior to laying a new cable and allows for the route to be cleared of any unwanted debris on the seabed that may interfere with the new cable being laid.
However, the subsea load pin has become a flagship product, largely because it can be used in such a variety of applications and can be easily customised to fit into a multitude of original equipment manufacturer (OEM) products that are utilised by the industry.
As the DLM-Vulcan partnership proves, it takes a multifaceted approach to successfully serve wind energy these days, and the sector doesn’t differentiate between the hardware and software it requires. Both are necessary. It’s about solutions.
Halford explains, “When laying cable, clients want to see that the operators are looking after it. This is especially important when getting into insurance claims, as subsea cable costs are astronomical. Being able to prove that the cable has not seen an overload could be critical in proving to the owner that the installer has taken care of and installed it correctly. This can be done by using load cells and combining them with our data-logging software or linking outputs from the load cells’ displays to the ships’ survey suites.”
Wind energy network
The potential of the wind energy sector can be further demonstrated by looking at the complexity of the supply chain, which needs load cells, plus load monitoring and cable working equipment, from manufacturing to decommissioning processes.
Tensile link load cells have been used to accurately weigh turbine blades during manufacture, and they can be used when lifting monopiles into the sea using offshore cranes. During transportation, which often involves specialised vehicles, links and shackles are used to provide load readings, which helps to ensure the safe transit of oversized parts. Then comes the PLGR and route clearance tools.
“Once operational,” says Halford, “Wind farm operators use subsea data-loggers to continuously gather information, even when an end user isn’t physically on site. We have completed some customised applications where we measured and logged the movement of inter array cables over time. Load pins and subsea links can also be used to measure tension in anchor lines in floating wind applications.”
That’s without mentioning service and maintenance, where DLM’s calibration and on-site engineering support services are required; and decommissioning, where, again, tensile links and shackle load cells are integral to safe lifting operations.
