Most of these systems, however, are invasive and complicated and require an outage to install.And since every key component needs a separate sensor, these solutions are often pricey too.
An alternative, developed by Sensei Solutions, is already proving highly cost effective and dependable.It uses infrared inspection but not in the handheld or gimbal mounted sense that has been common in the industry for many years.The Sensei system is based on a network FLIR fixed mounted cameras and intelligent automation software that monitors critical components continuously without the need for human intervention. Whenever a pre-defined temperature threshold is detected by a FLIR camera, an alarm is generated to a remote operator who can take the appropriate action.
“Continuous automated radiometry has many benefits,” explains Robin Thompson founder and CTO of Sensei Solutions. “This method is non-invasive, eliminates human error and mitigates the risk of greater failures.Also, one camera is able to monitor several assets at once.”
The FLIR cameras are teamed with SensEye AVR, Sensei’s video analytics system, which records thermal images as JPEGs and the frame by frame radiometric data captured by the FLIR cameras, allowing for precise pixel-by-pixel measurements. SensEye AVR analyses on-line data from virtually any substation device, automatically alerts and notifies critical changes in any reading or combination of readings and delivers data to SCADA and enterprise historian servers.
Secure solution
The condition monitoring concept was developed from a successful Sensei installation of FLIR automation cameras for intruder detection.The customer concerned wanted a robust system that would address the recurring problem of security breaches and copper thefts but Sensei realised that FLIR infrared technology could also be the ideal method for reading the temperatures of the company’s bushings, breakers and capacitor banks.
When combined with SensEye AVR, the FLIR cameras have now become Sensei’s preferred solution for electric substation condition monitoring and many successful installations confirm the efficiency of this system.A typical application is for a large data centre that owns its own substation.Here, Sensei installed nine FLIR A310f thermal imaging cameras to monitor eight transformer-circuit pairs and a manually operated disconnector.
These cameras are connected to the SensEye AVR software to monitor 12 ‘probe points’ in each camera’s field of view.An image is collected every 20 minutes, capturing high, low, mean and median temperatures for each measuring point.
“Not only has the customer boosted its security level by increasing the thermographic sampling from four times per year to over 26,000 times per year, it has also received a significant insurance premium discount because of this increased reliability,” Robin Thompson confirms.
The extremely rugged FLIR A310f can be installed almost anywhere to monitor the condition of critical equipment and other valued assets. The unit contains an uncooled microbolometer detector that produces crisp 320 x 240 resolution thermal images, making small temperature differences easily visible.It has a built-in lens with motorised focus; the ability to stream video over Ethernet to view live images on a PC; communication and power over Ethernet cable and it can be controlled remotely over the web and TCP/IP protocol.
Built in analysis functions like spot, area measurement and temperature difference are standard features.Alarms can be activated as a function of analysis, internal temperature or digital input and the camera automatically sends analysis results, IR images and more as an e-mail on schedule or at alarm.And as the FLIR A310f is Ethernet/IP and Modbus TCP compliant, all results can be shared to a plc.
Demonstrating reliability
An automated thermal inspection solution not only increases reliability, it also significantly contributes to company image.A manufacturer with its own electric substation has SensEye AVR installed with three FLIR A310f cameras to monitor transformer and circuit breaker bushings, switch gear jaws and manually operated disconnectors; the system is monitoring between 12 and 16 probes in each camera field of view.
In this case the AVR console display is located at the company’s headquarters where it serves as a reference for the management team and high value customers, demonstrating the reliability of plant inspection.
For some customers though, automated thermal imaging can make substantial cost savings from day one.For a large steel manufacturer, Sensei installed four FLIR A300 Series cameras.Two of these were in the melt room, focused on the melt container providing a live feed of current temperature and the other two units, in the transformer vault.On the first day of AVR monitoring the customer discovered three serious issues with the switchgear.This allowed the maintenance to take appropriate action to avert costly failure.