Intelligent Inspection

Online Editor

Tony Dale discusses thermal inspections for critical rig electrical systems.

Rig maintenance supervisors and engineers are traditionally focused on asset utility, preventing the impact of breakdowns by initiating checks and measures using crew technicians or third-party vendors, as detailed in the preventative maintenance (PM) manual, with time- and condition-dependent checklists to monitor and trend for equipment efficiency and functionality.

Although electrical systems are among the most reliable equipment, they do require periodic maintenance and inspection to ensure they are compliant and safe. Running equipment until it breaks may provide short-term savings, but this reactive maintenance approach will end up eroding operating efficiency and destroying reputation. Moreover, these effects are exacerbated if equipment cannot be accessed due to inherent operational and safety constraints. 

The practice of opening energised electrical enclosures is forbidden, controlled by permits, isolations and equipment interlocks – due to the potential of electric shock and arc-flash. This makes periodic PM checks into critical HV/MV systems nearly impossible unless the system is switched off.

Employing a safe system that is non-invasive (non-contact) will easily overcome the above restrictions and endorses an emphasis to ‘work smart and stay safe’ diktat within the site or rig fleet.

The adoption of a handheld thermal imaging camera (a system that enables the technician to see beyond their visual range and into the infrared (IR) spectrum – to see heat before a component glows cherry red) into the facility’s PM regime will help identify apparent temperature differences in electrical circuits, compared with their normal operating conditions.

Greatly Improved Safety

For instance, by inspecting the thermal gradients of cabling, trained users can effectively spot performance anomalies such as high resistance at individual crimps – due to loose terminations, imbalances and overloading. When thermal imaging is combined with the retrofitting IR windows, it greatly improves rig safety and critical system availability for testing when energised.

Thermographic surveys combined with infrared windows focus on prevention, enabling timely and effective inspections and allowing critical systems to be properly checked.

With this approach, results are obtained safely, and immediate ROI savings are achieved.

IR windows are typically round, with a crystal or polymer lens and come in three diameters: 50mm, 75mm and 100mm; with the client wanting them fitted to: transformer housings; switchgear cabinet doors or their rear panels; and the main engine terminal box covers, including internal cabinet dead-front screens (since plexiglass is non-transmissive to infrared energy).

When fitted, IR windows allow for the safe visual and thermal acuity into locked enclosures.

Implementing both practices will offer operators the potential to identify an extreme hotspot in vital equipment (albeit adjustment is needed to the thermal camera settings to compensate for scanning through the IR crystal or polymer viewing pane).

When a thermal camera and IR window are combined, they become mutually advantageous and a low-cost solution to direct rig maintenance crews to the exact item to expedite early repairs, prevent failure and critical system outage.

During the current energy security fears, a structured, all-inclusive maintenance approach is needed to achieve high utility and productivity while maximising margins and driving profitability. Furthermore, the use of a thermal imaging camera and retrofitting IR windows can be realised as an intelligent lever for an asset becoming more competitive. It also allows the operator to be seen as robustly supporting the rig's safety-conscious culture, which is essential given the considerable proportion of operating costs it represents.

Tony Dale is managing director of Geotherm

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