Instrumentation Monthly Test | Measurement | Control
Within the power generation industry, preventative maintenance programmes have to be rigorous to minimise power loss to its customers and the cost of failure. Nevertheless, some critical systems remain extremely vulnerable through their inaccessibility. 
Isophase bus, bus way and bus bar systems are typical examples and they usually have no redundancy or quick replacement options. But, thanks to IRISS, new electrical maintenance safety devices (EMSD) have been developed so faults in these hard-to-reach systems can be detected before they can cause an outage.
The current method of determining the health of an isophase bus system is indirect thermal inspection whereby temperature is measured on the outside of the casing – a process that isn’t very reliable and can be time-consuming. In addition, this form of thermal inspection can’t provide an image of fault or the actual temperature at the source of the defect. The internal air gap in the isophase bus acts as an insulator and the heat energy generated by the fault has to travel across the air gap and warm the large outer casing of the bus system.
Results can also be skewed by ambient temperature and harsh weather if the system is outdoors.
To eliminate these problems, IRISS has introduced FlexIR EMSD, a large format infrared and visual inspection window with polymeric lens that is specifically designed for the power generation and large power user market.
The insertion of an IRISS FlexIR into the isophase bus system allows the maintenance engineer to complete a visual and thermal scan of the bus joint whilst it is under full load. This allows any fault to be seen and identified in infancy so its severity can be graded and the problem scheduled for repair.
FlexIR can also be easily removed and, once refitted, the isophase system can be re-energized and the repaired joint inspected with the thermal imaging camera to verify its effectiveness.
Key to the design of the IRISS FlexIR is the company’s characteristic, polymeric lens material that allows the window to be any size or shape and even curved. It is unaffected by mechanical stress and when reinforced with specially engineered grills, the polymer optic is capable of resisting a sustained load. It is also shatterproof and highly resistant to chemical and environmental attack.
IRISS EMSDs are collectively providing a cost-effective way for companies to comply with all of the established and changing standards for maximum inspection safety whilst minimising commercial risk. They allow switchgear to remain closed, removing all possible triggers for arc flash, and become data collection points for vital equipment.
