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3.9 IoT For Oil and Gas Industry 199
deployed in a wide variety of use cases, ranging from monitoring to safety
critical applications. The main obstacle for a rapid adoption of wireless technologies
is no longer the lack of suitable technologies; rather it’s the lack of
established industrial standards. Without standards, there is no effective means
to achieve the interoperable, multi-vendor solutions which is required by customers.
In addition, as many technologies operate in the same frequency band,
standards are also required to ensure co-existence of wireless technologies (as
wireless is an open medium).
The first wireless standards for process automation emerged only some
years ago but already in 2002 the CORD project started investigating the possibility
to do wireless condition monitoring on small AC motors. The project
had mapped degradation mechanisms of these motors by interviewing specialists
from the Oil companies and found that the most common and costly
failure modes were bearing breakdown due to vibration and insulation failure.
In 2004 the project tried to identify and assess different technologies and techniques
to monitor the degradation mechanisms and the conclusion was that
none of the existing “off-the-shelf” condition monitoring systems seemed to
meet the requirements. In 2005 the project started to evaluate if and how the
monitoring could be achieved by utilizing micro technology and in 2006 the
spin-off project Wireless Condition Monitoring project was formed.
Why Motors
Why was condition monitoring of small AC motors selected? Some of the small
AC motors on an oil rig are highly critical with respect to regularity, some are
critical with respect to safety if for instance placed in EX (explosion proof)
zone. Larger machines are normally always monitored but for these smaller
AC motors the then prevailing maintenance strategy was “run-to-failure” due
to their high numbers — of up to 1000 units per offshore installation — and
the cost associated with monitoring them. A failure leads to high maintenance
costs estimated to approximately 10 000 per motor and per repair with a
bearing failure being the most critical, causing the larger cost. The definition
of AC motors is that they are below 400 kW in size and normally run at around
3000 r/min. At an oil rig these are the motors used to drive equipment such as
pumps, air compressors and fans.