Page 43: of Offshore Engineer Magazine (Mar/Apr 2022)

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TECH FEATURE HKZ side, Joris Engelen, TenneT’s Platform Project Lead, said, duced at the wind turbines, which have yet to be installed, “When designing and building our jackets, scenarios are from 66 kV into 220 kV, and will then transport the elec- taken into account that a ship of limited size may collide tricity is shore via subsea cables, to an electrical substation with the jacket. After the initial fright of the collision, we at the Maasvlakte. set up and implemented an extensive investigation plan At this substation, TenneT said, the voltage is converted in cooperation with the parties involved. The jacket is ex- into 380 kV. Finally, the electricity is transported to the pected to be in operation for many years.” high voltage grid via high voltage station Randstad 380 kV

He said that it was a relief that the inspections and the Zuidring, TenneT explained.

investigations showed that the topside installation could Petrofac was responsible for the engineering, procure- proceed safely and as scheduled. ment, construction, and offshore installation of the HKZ

The repairs of the damage on the jacket are scheduled to be carried out after the topside installation.

While the incident had potential to negatively affect the project budget and schedule, there is also a silver lining in that it immediately prompted the industry to search for ways to prevent similar incidents from happening again.

Read more on this in the box below right.

HKZ Alpha ready to connect

Following the successful installation, the HKZ Beta

High Voltage Alternating Current (HVAC) offshore trans-

Credit: TenneT former platform with a 700MW capacity, and built by

Petrofac and Drydocks World Dubai, will now be prepared

HKZ Jacket Damage for the connection to Vattenfall’s wind turbines.

According to TenneT, the Hollandse Kust Zuid Alpha transformer platform, to be used for a connection for off- shore wind farms Hollandse Kust Zuid I and II is now ready for use.

“TenneT completed the installation and energization of the offshore grid connection. Wind farm developer Vatten- fall can now connect the wind turbines to the high voltage grid.” TenneT said in a statement sent to Offshore Engineer.

Marco Kuijpers, Director of Large Projects Offshore, said, “With the energization of the Hollandse Kust Zuid

Alpha connection, the offshore grid that TenneT is build- ing in the North Sea is starting to take shape. Hollandse

Kust Zuid Alpha is the ? rst connection of an offshore wind farm to the Maasvlakte and has a capacity of 700 MW. The energization of Hollandse Kust Zuid Beta later this year will add another 700 MW from wind farms Hollandse

Kust Zuid III and IV.”

As mentioned, the platforms form part of the grid con- nection that connects the offshore wind farm zone to the

Dutch mainland at the Maasvlakte.

Located 20 km off the Dutch province of Zuid-Holland, the Hollandse Kust Zuid (HKZ) wind farm zone covers an area of 235.8 km2.

The platforms will convert voltage of the electricity pro-

Credit: TenneT march/april 2022 OFFSHORE ENGINEER 43