Submarine cables have always played a crucial role in offshore projects; earlier they were used mostly for oil and gas transportation. Recently, submarine power cables are used to connect power grids and transmit renewable energy supplies such as wind, wave, and tidal. The recent development has further expanded the subsea cable market as it is noticeably booming and generating massive revenue.
Regardless of the technological innovations and advancements in the submarine cable industry, Submarine cables are still prone to damage and failures and due to this, they need to be carefully handled from their manufacturing time to their maintenance period. Cable design should be of paramount importance as any error could shut down the entire project until the repair is done and most repair mechanisms are very costly to handle.
But despite being part of advanced technology, submarine cables remain relatively easy to damage.
Maintenance Plan Of Submarine Power Cable
Having a cable maintenance plan is very crucial as this will promote orderliness and activity recording as well. It also shows a series of measures strategized to reduce damage and downtime. The maintenance plan is divided into two namely:
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The preventive and corrective maintenance plan: which includes necessary information required for cable monitoring, inspecting and best repair systems.
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Intervention plan: this is usually applied when there's an emergency shutdown due to unnoticed cable damage or failure.
Cable Maintenance Practices
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Prevent and remove physical stressors as well as extreme duty stressors.
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Follow best practices: install and maintain excess voltage protection, make sure to always perform IR inspection of connectors, handle offline 50/60Hz Partial discharge(*PD) testing to Insulation defects (*ID), reduce or remove excess voltage tests such as fault location thumping as well as withstand/hipot testing and also bear in mind that most cable system insulation fails due to the erosion process witnessed in PD so make sure to always care about that (Partial discharge also known as micro arcing is an electric discharge that does not fully bridge the insulation which can give rise to high focus of electric stress, loss of right solid insulation or both.
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Cable asset management standards start from the quality tests imposed on cable and accessory manufacturers by ICEA-Insulated Cable Engineers Association, and IEEE-Institute of Electrical and Electronics Engineers. These standard quality tests are done to ensure the performance of newly built system components before shipping out for deployment.
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The major aid for cable longevity is beginning as early as possible to pursue quality and reliability in every cable’s life. Minimize all excesses and maintain all good attributes of the cable. Push for good repair techniques anytime cable becomes faulty. When repairs are done, make sure that the over-voltage protection is sufficient to avoid overloading and other cable issues.
Reliability is key when dealing with Subsea cables. Submarine cables used for renewables are meant to be of high-quality and low maintenance cost as such required specifications mandated must not be compromised so as to encourage cable sustainability. Subsea cables are laid or buried in seabeds at extreme water depth conditions which are threatened by many risks and disturbances due to the nature of their deployed location. For instance, Over €350 million of insurance claims have been made just in the past seven years.
Cable Monitoring Best Practices
Considering the rate of cable damage and its effect on the entire project cost and others, routine manual monitoring and inspection practice isn't enough for early detection of cable faults so therefore high- tech monitoring activities should be applied for a full cost-effective management operation. These monitoring systems detect even when cables are prone to danger and also provide early signals when cables are faulty or damaged which reduces downtime as well as total project running cost. In addition, Integrated condition monitoring such as Temperature and Strain monitoring, Partial Discharge Monitoring(PD) , and a few others can be used as an effective asset management tool and a preventive maintenance system. Just by implementing a reliable and continuous monitoring tool, one can save a lot of funds as well as time.
Modelling
To reduce external risk and also prevent some avoidable occurrences, Models are generated. Modelling is the act of collecting and recording data of previous happenings or projected occurrences so as to be used in predictive analytics in the future.
In conclusion, cable maintenance is key in every cable's life as it can determine how long a cable lasts. The cable can be produced excellently but with poor management and check-up, won't reach its peak therefore, endeavor to use the best maintenance and repair systems so as to encourage cable reliability and validity. Continuous monitoring is needed to run a cost-effective project.
