What is Thermography?
- Thermography is a technique of analyzing the thermal characteristics of an object from its infrared image, captured through non contact thermal imaging device.
- Infrared thermography allows us to see heat energy radiated by objects (Both cold and hot bodies emit this type of energy).
How Thermography is Useful?
- Temperature is one of the first observable parameters that can indicate the condition of operating electrical equipment. Heat is a by-product of all work whether is it electrical, mechanical or chemical.
- Thermal energy not in control will cause failure in the equipment.
- Thermography allows us to detect the temperature of the object from the thermal energy emitted.
Applications-
In Switchyard: Corona has the potential to increase the temperature, which can result in system failure. To detect this thermography survey is required.
For Transformers: Infrared imaging of the transformer can often detect oil level and radiator convection cooling problems.
For the Batteries: can detect the individual faulty cells by measuring the temperature without contact,
At the Electrical Panels: Infrared thermography is used to perform Preventive Maintenance inspections-
Broadly the following can be observed-
- Loose connections / terminations,
- Oxidation at the cable termination points,
- Dust deposition at terminations,
- Defective lug crimping, overloaded or imbalanced circuits,
- Faulty breakers, damaged switches, faulty fuses and other hazardous electrical conditions. Electrical hazards continue to threaten safety of people and property in the form of shocks, burns, injury, fire and explosion. With electricity having become an indispensable part of our life, electrical risks are to be managed effectively.
- In process industries, fires due to electrical reasons are very probable, especially in industries that handle flammable chemicals. In service industries such as information technology, telecommunications, banking and other commercial establishments, business interruption losses due to electrical hazards (fire in server room, damage of expensive communication equipment, loss of data, fire in cable gallery, etc.) could be substantial.
- Typical scope of study
- Verification of statutory compliance with respect to Central Electricity Authority/Indian Electricity Rules.
- Physical inspection to identify electrical hazards (shock, fire, explosion, overloading) and to suggest electrical safety solutions
- Review of plant lightning protection system (need, adequacy, installation and maintenance)
- Review of static electricity hazards in the plant operations (if applicable)
- Review of hazardous area classification and selection of flameproof electrical equipment in the plant, including maintenance aspects (if applicable)
- Review of electrical preventive maintenance system (including tests, documentation, history cards, etc).
- Review of electrical accidents and near misses in the plant to identify the root causes
- Review of electrical systems & procedures (work permits, interlocks, lockout tags, etc).
- Review of the importance given to electrical safety in the company safety policy, safety committee, continuous electrical risk identification, etc.
- Assessing the integrity of insulation of cables by carrying out insulation resistance tests on a sample basis
- Review of the earthing system (installation & maintenance aspects), including sample earth resistance tests
- To identify areas of overloading by carrying out load current measurements and compared against cable current carrying capacity calculation
Methodology
- Pre-Audit Questionnaire
- Audit
- Physical Inspection at site
- Tests – Thermography Voltage / Current /Power measurements, Healthiness of grounding, Lightning Protection etc.
- Discussion
- Document review
- Report Submission