Innovative double redundancy fail-safe system for oil rig

The task

Tasked with designing a revolutionary control system for a crane on board the Johan Sverdrup platform being built by Aibel, Norway, Banelec’s vast experience in hazardous area systems was called to the test.

Due to the location of these high spec gantry cranes on the blowout preventer (BOP) deck of a new oil rig, the safety of these cranes is of critical importance. Any failure in a system that is in this location could potentially lead to a dangerous situation, which is why a new double redundancy fail system needed to be designed.

What we created

In the event of a crane failure on the rig, this design created a backup system providing a safe and reliable method of recovery. If there are any failures during the vital lift, the control system on these cranes switch to an Emergency Operating System (aka EOS system). The crane will be shut down, then the backup EOS system is available to use in slow speed to keep the crane in use, to recover any items which require lifting to make the area safe in an emergency.
This ensures the safety of both personnel and the area around the crane before they investigate the problem which has occurred. These controls offer a second full basic system which can operate the crane in these circumstances.

The result

This was a ‘first’ for the offshore industry, with the control system being completely duplicated within the same enclosure to provide this second, totally independent system in the event of a failure of the primary system. It does this through its introduction of top safety PLe to the design. This is controlled by a software programmable safety controller and corresponding safety modules and relays, a master and slave relay set, which switches the system across in the event of an issue.