I gather information, look at what’s already on the market and then think of better technologies.Vemund Kaarstad, Process Industries & Drives
For the construction of offshore wind farms and for underwater oil and gas production, you need jack-up platforms with legs of up to 200 meters that are anchored in the seabed. Nowadays, this is generally done with an automated control unit developed by Vemund Kaarstad. The busy expert from Process Industries & Drives works in Oslo, Norway.
The giant constructions spend day and night out in the open sea, braving the wind and waves for decades. Once a platform stands firmly on the seabed, nothing can push it over that easily. The delicate phase is its installation at sea: Typically, these huge platforms have three or four legs that can be up to 200 meters long. It can take as many as 96 motors to lower the legs down to the seabed and anchor them there. Then the motors jacks the entire platform above the water.
“In the past, one of the legs would sometimes break off in the process,” Kaarstad explains. Investments in the millions thus went down the drain – not to mention the danger to the people on site.
Kaarstad developed a control system, complete with a control strategy, that automatically lowers the legs’ motors and controls the load on each leg as the jack-up platform is raised above the water. All of the variable-speed electric motors are equipped with sensors and an electromechanical brake that transmits the speed of each motor to the control system. One of the motors on each leg features a stopping function to prevent the entire system from being lowered too quickly. And the brakes, too, are controlled in an automated and coordinated manner. Kaarstad optimized the design together with colleagues from Siemens Netherlands and in cooperation with the Dutch construction company GustoMSC.
The first prototype of the GustoMSC-Siemens-system already convinced several major underwater oil and gas production companies. Today, jack-up platforms are also used in the construction of offshore wind farms. Siemens has sold more the system more than 70 times so far, with further major orders already in the pipeline.