HØVIK, Norway – DNV GL has released design guidelines for closed-bus dynamic positioning drilling.
While closed-bus drilling saves fuel and maintenance costs, a closed-bus system is more complex and tightly integrated then open bus, and this makes it more demanding to build, verify, and operate safely, said DNV GL.
To manage these risks, DNV GL has issued an Offshore Technical Guide on how systems based on closed bus-ties configuration can be designed and verified with additional protection and monitoring facilities, ensuring integrity and robustness. The guidance addresses the issue of testing by recommending test requirements that safeguard equipment from damage during testing, while at the same time obtaining sufficient evidence of robustness.
Approval of a closed-bus DP unit requires validation of the fault tolerance of the connected system, including live short-circuit testing of worst case failure modes. Extensive experience with operations and testing proves that live earth fault and short-circuit tests are necessary.