Arc Flash & Protection Coordination Review - Reducing Incident Energy Without Major Switchgear Replacement
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Katoni Engineering supported a client in delivering an arc flash and protection coordination review on a live offshore drilling asset, as part of an ongoing electrical safety and operational risk-reduction programme. Earlier assessments had identified elevated arc flash incident energy across the rig's HV and LV distribution system. The question was how to bring that exposure down without the cost and downtime of major switchgear replacement, and without compromising how the network behaves under fault.
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The challenge
The asset operates across a range of dynamic drilling and marine configurations, which means fault levels and protection coordination requirements shift across the electrical system rather than staying fixed. Anychange to protection therefore had to hold up across multiple operational states, not just one.
That made the task a balancing act between four competing demands:
- Reducing arc flash incident energy exposure
- Maintaining selective protection coordination
- Preserving operational resilience
- Avoiding unnecessary loss of healthy sections of the network
As with many ageing or operationally flexible offshore assets, the difficulty wasn't simply lowering protection settings. It was ensuring the system continued to behave predictably and safely under fault conditions once those settings changed.
Our approach
Katoni expanded the client's existing ETAP arc flash model to carryout detailed protection coordination and Time-Current Coordination (TCC) assessment across the rig's electrical network. The review included:
- Multi-scenario operational modelling
- HV and LV protection coordination assessment
- Arc flash reassessment studies
- Review of relay and trip unit settings
- Assessment of operational protection trade-offs
- Identification of practical, implementable risk-reduction opportunities
Throughout, the work weighed personnel safety improvement against the operational realities of offshore drilling and marine power systems. Where appropriate, revised protection philosophies and future maintenance-mode concepts were also considered, to support safer intrusive maintenance activities down the line.
The outcome
The study demonstrated that meaningful reductions in arc flash incident energy could be achieved through targeted protection review and system modelling without major switchgear replacement.
Katoni provided the client with:
- A clearer understanding of network protection performance
- Reduced arc flash exposure across key switchboards
- Operationally pragmatic protection recommendations
- A technically defensible basis for future modifications
- Improved visibility of protection coordination limitations and opportunities
The project reinforced a principle that runs through our electrical work: meaningful safety improvement comes from combining detailed power system analysis with genuine offshore operational understanding - not from defaulting to the most intrusive, most expensive option.
Services provided
Arc Flash Hazard Assessment · Protection Coordination Studies · ETAP PowerSystem Modelling · Short Circuit Analysis · Protection Relay Review · Electrical Safety Engineering · Offshore Power System Studies · HV/LV Distribution System Assessment
Software & standards
ETAP Power System Analysis Software · IEEE 1584-2018 · NFPA 70E · IEC 60909
Facing elevated arc flash levels on your asset? Get in touch - replacement isn't always the answer.
Speak to Our Team
Have a question or need support? Reach out and our team will get back to you promptly.
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