THERMOGRAPHY
What is Thermography?
Thermography is the most effective test method of analysing the thermal characteristics of an energized electrical component from its infrared image, captured through a non-contact thermal imaging device. This technique is basically used to detect poor connections, unbalanced loads, deteriorated insulation, or other potential problems which causes excess power use, increased maintenance costs, or catastrophic equipment failure resulting in unscheduled service interruptions and equipment damage or other problems.
Why do we need Thermographic Inspections?
As per NFPA or National Fire Protection Association, 10%of the fires happening are associated with electrical system failures, like failure of terminals, electrical insulations and related components and thus Electricity at Work Regulations Act 1989, Health and Safety at Work Act 1974 and BS 7671 (IEE Wiring Regulations 17th Edition as amended) have suggested that electrical infrastructure should be regularly maintained and tested to ensure compliance with Safety guidelines.
A Thermographic Inspection is a must for the sectors having high power consumption, multiple branch circuits and distribution subsystems, or heavy equipment activity. Businesses with high electrical demands should have a thermographic scan performed annually on all critical electrical systems such as Electrical panels, Switchgears, and Transformers. Based on the scan results, a schedule should be prepared to plan annual thermography inspection activity based on the types of equipment, power consumption, and age of the electrical systems. A Thermography Expert can assist a business owner to determine what and how often to conduct Thermography inspections.
Thermography is the most effective way to monitor temperatures in electrical panels and other electrical Assets. It helps in identifying the critical Hotspots in electrical systems that may cause fire incident, abnormal heating which may result in equipment damage and even break down causing business Interruptions. So as to ensure uninterrupted business operation, Thermography inspection should be carried out by appointing qualified Thermography experts at least once in a year.
One of the main advantages of Thermography inspections is the cost effectiveness that comes from energy conservation and reduction in shutdown and repair and replacement charges. High resistance in circuits causes an increase in current flow which results in increased power consumption. Moreover, increased current flow may cause severe electrical circuit components, like circuit breakers, fuses and transformers to collapse prematurely and these may result in higher repair and maintenance costs and business interruptions.
How does Thermography work?
Thermography scan is performed by an infrared camera or a thermal imager. These devices measure the natural emissions of infrared radiation from a heated object and produce a thermal picture. Modern Thermal Imagers are portable with easily operated controls. As direct contact with the system isn’t needed, testing can be done under completely energized state leading to no loss of production or downtime.
Thermography, also called infrared inspection, is based upon the sensing of heat emitted from the surface of an object in the form of infrared radiation. Most electrical Thermography work is qualitative, that is, it simply compares the thermal signatures of similar components. A thermal signature is a snapshot at a single point in time of the heat being given off, or emitted, from an object. It is straightforward with three-phase electrical systems because under normal conditions the phases almost always have easily understood thermal signatures.
Energized electrical systems generate heat because of electrical resistance. The amount of heat generated is related to the amount of current flowing through the system and the resistance of the individual system components and connections within the system. As components deteriorate, their resistance increases, causing a localized increase in heat. Similarly, a poorly made connection will have higher resistance than a well-made connection, along with a higher temperature profile. Thermography may be used to detect these temperature differences.
What are the benefits of Thermography?
- Determines whether the electrical components and system have been properly installed and are not damaged
- Minimal or no downtime
- Reduces risk of equipment failure
- Ensures electrical safety
- Improves insurability
- Reduces liability exposure of the designers and installers
- Improves system performance
- Determines whether components and systems operate properly and meet the design intent
- Determines if components and systems are in compliance with the project specifications and design
- Reduces construction schedule delays
- Saves money
Thermography Applications
Thermographic inspection is performed on Electrical systems such as –
- Electrical Panel
- Electrical DB
- Motor
- Generator
- Transformer
- HT & LT Breaker
- Battery
