Infrared Inspections

Description:

Infrared thermal surveys, also known as thermographic inspections, involve the use of infrared cameras to capture thermal images that illustrate the temperature distribution of electrical equipment while it's in operation. This non-contact, non-destructive testing method detects irregular heat patterns that may indicate potential problems such as loose connections, overloaded circuits, or other anomalies in electrical components.

Common Issues

Overheating Issues:
Infrared inspections can detect overheating electrical components such as wires, switches, circuit breakers, and connections. Overheating is a common precursor to electrical failures and can lead to fires or equipment damage. Detecting these issues early can prevent catastrophic failures.

Failure Prevention:
By identifying and addressing potential issues before they escalate, you can prevent unplanned downtime in your facility. Downtime can be costly in terms of lost production, revenue, and repair expenses.

Increase Equipment Lifespan:
Regular inspections can extend the lifespan of electrical equipment. Overheati issues early can help equipment last longer.

IR Fuse Image

Specific Applications:

Preventive Maintenance:
Regularly scheduled infrared surveys can help in detecting early signs of failure in electrical systems.

Quality Assurance:
Verifies the integrity of electrical installations and repairs.

Condition Monitoring:
Continuous monitoring of critical equipment can prevent catastrophic failures and unscheduled downtime.

Energy Audits:
Identifying heat losses in electrical systems can lead to energy savings by addressing inefficiencies.

Pros:

Non-Invasive:
Does not require shutdown or contact with the equipment, allowing for ongoing operations without interruption.

Early Detection:
Identifies potential failures before they lead to major damage, reducing repair costs and downtime.

Safety Enhancement:
Reduces the risk of fires and increases safety by early detection of overheating parts.

Cost Savings:
Helps in saving costs by preventing large-scale repairs and energy wastage.

Cons:

Initial Cost:
The equipment and expertise required for infrared thermal imaging can be expensive

Training Requirements:
Requires trained personnel to interpret thermal images accurately.

Limited Reach:
May not detect issues deep within enclosed or compact systems unless there's a clear line of sight.

Periodic Inspections:
Being a snapshot in time, it requires periodic surveys to ensure continuous protection.

NETA Test Procedure
Thermographic Survey
NETA ATS-2017
Thermographic Survey
1. Visual and Mechanical Inspection
  1. Perform thermographic survey when load is applied to the system.
  2. Remove all necessary covers prior to thermographic inspection. Use appropriate caution, safety devices, and personal protective equipment.
  3. * Perform a follow-up thermographic survey within 12 months of final acceptance by the owner.
2. Report

Provide a report which includes the following:

  1. Description of equipment to be tested.
  2. Discrepancies.
  3. Temperature difference between the area of concern and the reference area.
  4. Probable cause of temperature difference.
  5. Areas inspected. Identify inaccessible and unobservable areas and equipment.
  6. Identify load conditions at time of inspection.
  7. Provide photographs and/or thermograms of the deficient area.
  8. Recommended action.
3. Test Parameters
  1. Inspect distribution systems with imaging equipment capable of detecting a minimum temperature difference of 1° C at 30° C.
  2. Equipment shall detect emitted radiation and convert detected radiation to visual signal.
  3. Thermographic surveys should be performed during periods of maximum possible loading. Refer to ANSI/NFPA 70B, 2010 Edition, Section 11.17.
4. Test Results
  1. Suggested actions based on temperature rise can be found in Table 100.18.
NETA ATS-2017
9. THERMOGRAPHIC SURVEY
1. Visual and Mechanical Inspection
  1. Inspect physical and mechanical condition.
2. Thermographic Survey Report

Provide a report which includes the following:

  1. Description of equipment to be tested.
  2. Discrepancies.
  3. Temperature difference between the area of concern and the reference area.
  4. Probable cause of temperature difference.
  5. Areas inspected. Identify inaccessible and/or unobservable areas and/or equipment.
  6. Identify load conditions at time of inspection.
  7. Provide photographs and/or thermograms of the deficient area.
  8. Provide recommended action for repair.
3. Test Parameters
  1. Inspect distribution systems with imaging equipment capable of detecting a minimum temperature difference of 1° C at 30° C.
  2. Equipment shall detect emitted radiation and convert detected radiation to visual signal.
  3. Thermographic surveys should be performed during periods of maximum possible loading. Refer to NFPA-70B.
4. Test Results
  1. Suggested actions based on temperature rise can be found in Table 100.18.
NETA ATS / MTS
TABLE 100.18
Neta Table 100.5

Temperature specifications vary depending on the exact type of equipment. Even in the same class of equipment (i.e., cables) there are various temperature ratings. Heating is generally related to the square of the current; therefore, the load current will have a major impact on ΔT. In the absence of consensus standards for ΔT, the values in this table will provide reasonable guidelines.

An alternative method of evaluation is the standards-based temperature rating system as discussed in Chapter 8.9.2.2, Conducting an IR Thermographic Inspection, Electrical Power Systems Maintenance and Testing, by Paul Gill, PE, 2008 edition.

It is a necessary and valid requirement that the person performing the electrical inspection be thoroughly trained and experienced concerning the apparatus and systems being evaluated as well as knowledgeable of thermographic methodology.