Project review
Deepwater installs new type of impressed current anode system to protect wind farms in the Irish Sea
Overview
In June 2005, Deepwater supplied and supervised the installation of seven (7) Vaulted Seawater Envelope (VSE) anode arrays on wind turbine monopiles in the Irish Sea. Each monopile was retrofitted with one VSE and one transformer rectifier. The wind farm is located in 8 m -10 m water depth. The VSE anode system minimizes the risk of snagging by fishing activities while maintaining a uniform circuit resistance when the system silts over. Assets to be protected included:
• 7 x Offshore Wind Turbines
The retrofit cathodic protection (CP) system consisted of:
• 7 x Vaulted Seawater Envelope Anode Systems (aka VSE)
• 7 x Transformer rectifiers
• 7 x DR-2 CD Monitors (part of the monitoring system)
Installation
The VSE assemblies were installed 10 m to 15 m from the base of the monopiles. Dual-armored single-conductor cable was routed from the VSEs, across the bottom to the base of the monopiles and then up through specially-installed I-tubes to the rectifiers located at the (+) 13 m elevation. The systems, including I-Tubes, were installed on all seven monopiles in a total of eleven work days utilizing a dive support boat with lifting “A” frame. In addition, DR-2 CD polarization monitors were installed to monitor the performance of the new CP system.
Image gallery
The installation vessel.
The VSE on bottom; the sacrificial anode to protect the frame and the scouring fronds are visible.
The I-Tube installed to house the power cable through the splash zone.
The VSE anodes in Deepwater's yard before being shipped to site.
Here, the VSE has already begun to silt over and self-bury.
DR-2 CD shown from above, installed on the monopile.