Thermal Imaging

The purpose of a thermographic survey of an electrical and power generation installation and distribution system is to identify areas where excessive heat is being generated that could lead to catastrophic failure of equipment, fire, loss of production and injury to personnel.

Introduction

Thermal imaging can also be used to record mechanical temperature measurements (such as the temperature difference across a cooler) or to detect potential failures (such a rise in bearing temperatures)

Rigtech technicians use the most up to date equipment and software available and our expertise in the drilling industry means that we can correctly interpret the information when surveying such equipment as SCR and VFD drives and other systems peculiar to the industry.

Although standards do exist for Thermal imaging surveys, the results of a thermal scan are largely a matter of interpretation, knowledge of the equipment/process and an individuals experience.

AN EXAMPLE STANDARD:

Military Standard For Evaluating Faults Located In Electrical Equipment Utilizing Temperature Data Obtained With Infrared Imaging Equipment:

TEMPERATURES RISE ABOVE AMBIENT:

  • 10ºC to 25ºC component failure unlikely but corrective measures required at next scheduled routine maintenance period or as scheduling permits. (Green Label)
  • 25ºC to 40ºC component failure probable unless corrected. (Yellow Label)
  • 40ºC to 70ºC component failure almost certain unless corrected. (Orange Label)
  • 70ºC and above component failure imminent. Immediately inform the person responsible for continued operation of equipment. (Red Label).

To this aim therefore our thermal imaging technicians are experienced rig personnel who are able to interpret the results technically.

In the past for example, we have been able to identify problems with SCR firing because one SCR Puck was running at a lower temperature.

Rigtech uses advanced solid state thermal imaging cameras combined with specialist software for the best results. The cameras are able to give ‘picture in picture’ results which help in the identification of the exact location of an anomaly.

The cameras is linked via blue tooth to a clip an ammeter which records current direct to the camera and helps in the report preparation

EACH SURVEY CULMINATES IN A REPORT WHICH WILL INCLUDE, AS A MINIMUM:

A database listing each item of equipment inspected.

A summary report of the survey.

Technical information of the thermographic imaging equipment used and a current calibration certificate.

A thermographic image page of each defect which will include a true life photo of the problem area for ease of identification

EACH PROBLEM AREA PICTURE IS ACCOMPANIED BY:

  • Date
  • Location Information
  • Circuit loading at time of inspection
  • Temperature Calculations
  • Colour-coded Temperature Intensity and/or Condition Significance Data
  • A Brief Comment Relating the problem in the Photograph and its likely cause
  • Suggested or recommended remedial action.

IN THESE EXAMPLES:

The left hand cable is showing an elevated temperature, but the fault is actually in the right hand cable which was broken and not carrying current to a mud pump. All the current was passing through the other cable.

Here the results show a high temperature in the right hand phase of a generator connection. The right hand photo shows there was no visible evidence of a fault.

Undetected faults might cause further problems as in the case of this burnt out generator. Here the generator stator windings have been destroyed

In this more obscure example, the ferrous cable glands mounted to a ferrous gland plate on a generator are causing eddy currents which are heating up the gland ferrules.

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