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The risk of blackouts and brownouts (a fall in voltage, typically causing lights to dim) are increasing on the power distribution grid due to ageing infrastructure and a lack of automation systems that monitor the condition of critical equipment at substations and elsewhere on the grid.

For example, transformer fluid leaks or internal insulation breakdown cause overheating that leads to failure but many utilities don’t have automated thermal detection systems that reveal these problems.

Whatever the cause, a critical substation failure may cascade into a series of failures and impact massively on banking facilities, security systems, manufacturing plants, food refrigeration, communication networks and traffic control systems.  Of course, the electric utility also stands to lose huge amounts of revenue and incur high costs in getting its systems up and running again.

Although electric utilities have, for many years, used hand-held thermal imaging cameras to monitor substation equipment, the adoption of permanently installed systems are relatively new but certainly on the increase.  These provide continuous early warning of impending equipment failures.

These systems employ advanced sensing and measurement technology control methods and digital communications. They anticipate, detect and respond rapidly to problems, thereby reducing maintenance costs, the chance of failure, a blackout and lost productivity.

An example; one large utility discovered a hot bushing rod in a substation transformer and repaired it at a cost of only £11,000.  A similar problem that occurred before the company instituted its thermal imaging programme resulted in a catastrophic failure that cost more than £2 million.

Typical substation components whose thermal signatures are precursors to failure include power transformers (oil levels and pump operation); load tap changers (oil levels, other internal problems); insulator bushings (oil levels and bad connections); stand-off insulators (moisture, contamination, degradation); lightning arrestors (degradation of metal oxide disks); circuit breakers (oil or SF6 leakage); mechanical disconnects (bad connections and contamination); control cabinets (wear and tear on fans, pumps and other components) and batteries.

What is thermal imaging?

The principle of thermal imaging is ‘many components heat up before they fail’.  Secondly, all objects emit thermal radiation in the infrared spectrum that is not seen by the human eye.

Thermal imaging cameras convert that radiation into crisp images from which temperatures can be read.  This non-contact temperature data can be displayed on a monitor in real time and sent to a digital storage device for analysis.

The cameras do not require light to produce images and can see hot spots well before excessive heat or loss of insulation leads to failure.  They can be mounted in all-weather housings and placed on pan/tilt drive mechanisms to survey large areas of a substation.

Differences in the heat signatures of electrical components and their surrounding background are recognised and compared to temperatures of similar components in close proximity.

Built-in logic, memory and data communications allow the cameras to evaluate the temperatures in the images with user-defined settings and send that data to a central monitoring station for trend analysis, alarm triggering and the generation of reports. The devices can even notify managers in remote locations of abnormal conditions by sending an email.

Typical system configuration

In co-operation with automation system suppliers, a quality camera manufacturer can create customised thermal imaging and non-contact temperature measurement systems for substations. They can automatically perform site patrols and monitor equipment temperatures without human supervision. The video images and their temperature data are carried over Ethernet, wireless or over fibreoptic cables to an appropriate interface that communicates this data to the central monitoring location.

FLIR Systems specialises in technologies that enhance perception and awareness.  The company brings innovative sensing solutions into daily life through its thermal imaging and visible light imaging technology and systems for measurement, diagnosis, location and advanced threat detection.  Its products improve the way people interact with the world around them, enhance productivity, increase energy efficiency and make the workplace safer.

FLIR Systems has six operating segments – surveillance, instruments, OEM and emerging markets, maritime, security and finally, detection. Of these six, ‘instruments’ is of greatest interest to trade and industry and the second largest segment in the company’s portfolio. This division provides devices that image, measure and assess thermal energy, gases and other environmental elements for industrial, commercial and scientific applications.

These products are manufactured across five production sites, three in the USA and two in Europe; Sweden and Estonia.

A model to suit every application and budget
The options that FLIR Systems provides for measuring temperature and studying thermal performance have never been greater.  Not only does the company offer a huge range of models to suit all thermal application needs but the technology is also affordable and very easy to use.  Thermal cameras now come in various shapes, sizes and degrees of sophistication and FLIR continues to invest heavily in the development of new and complementary technologies to differentiate itself from competitors.

An important milestone in the development of thermal imaging has been the introduction of the FLIR Lepton® core, a micro longwave detector, the size of a mobile SIM.  This has allowed thermal imaging to be repackaged to meet the needs of an even wider audience and, in combination with another new technology called Infrared Guided Measurement – IGM™ – has led to the development of a range of test and measurement meters with imaging capability.

Another important growth area for FLIR thermal imaging is in continuous monitoring to assure quality and safety.  Through its introduction of discrete fixed mounted thermal cameras which are fully compliant industry standard plug-and-play protocols, FLIR Systems has provided industry with infrared machine vision which is instantly ready for quick and easy network installation.

Protecting assets and people from fire is an area for which thermal imaging is least known but, thanks to FLIR Systems’ development, it is now one of the most cost-effective methods available.  Its application flexibility and rapid return on investment present an attractive proposition for any site or safety manager.

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