Information about the conditions of electrical distribution systems gathered through Infrared Thermography is always correct and reliable. It is a determining factor in the supply of uninterrupted power to the consumers. Ideally, whenever a fault occurs, you will have to switch off the supply, which might lead to dissatisfied customers and heavy financial losses. On the other hand, infrared Thermography offers multiple advantages, including piecemeal inspection, quick identification of the defects, and diagnosing other components in their starting phase, preventing energy losses, short circuits, and expensive repairs.
How does Thermography work?
Infrared scanning works through heat sensing, better known as ‘heat signatures,’ emitted from any surface or object in the form of radiation commonly referred to as infrared radiation. To measure these infrared radiations in either temperature or value, various test instruments are used to find the object’s condition when they are measured.
How can Thermography be used to inspect Electrical Distributions?
Electrical installations generate heat due to electrical resistance. This circulation of heat is directly related to the current in the electrical panels, elements, and connections within the entire power system. When the conditions of the elements begin to deteriorate, their power of resistance also increases, resulting in high heat. Likewise, it will have a high resistance in a poor connection compared to a fully functional connection.
Application of Thermography
Infrared imaging professionals can detect the distribution elements in terms of heat patterns, faulty cables, broken wires, and other related problems to prevent electrical system failures. There are two categories of separate inspection, which are:
- Qualitative Inspection – In this case, you need to draw a pattern based comparison to temperature differences. This method is an excellent way to measure electrical distribution systems in a precise manner.
- Quantitative Inspection – When there is a significant difference in temperatures, you can move on to quantitative inspection after considering several aspects, such as emission, wind speed, spatial resolution, optical resolution, and temperature.
Switchgear Thermography
Vast amounts of investments are made towards infrared viewing ports for switchgear. Thus, you can carry out the inspections without removing the ports, which allow the workers to avoid mishaps during the inspection process. Installing cameras and imaging devices is the best way to avoid future infrared scanning failures of vital equipment. Often, the switchgear assemblies are compromised with faulty pieces of heaters. As a result, these heaters increase the switchgear’s temperature slightly higher than the ambient temperature to prevent condensation daily or seasonal changes. The proper functioning of the strip heaters and their increased efficiency reduces the potentiality of a power failure.
Methods of Inspection and Analysing Electrical Systems
Earlier, the options of inspecting the electrical systems were limited to few options. To check the electrical faults it is manually done by switching off the entire power systems. The staff members had to rely on specific tools and equipment to find any issues. Interpretation of heat was performed through thermocouples, which is a contact featuring technique. The staff members started using a radiometer; a non-contact thermal device pointed towards the faulty equipment to find the problematic area.
However, with new developments in electrical technology systems, analyzing and solving the issue through infrared scanners has become pretty much simple. Infrared imaging is one step up of radiometers. These thermal cameras’ function is to measure and display the infrared radiation’s temperature through a process known as ‘thermogram.’ The use of Thermography is not dependent on any visible illumination to see the infrared radiation emitted by these objects.
Benefits of Thermographic Survey?
It is estimated by most of the insurance carriers that about 25% of major power failures occur due to faulty electrical connections. Therefore, several insurance companies provide extra support in the facilities for carrying out the annual thermal inspections.
Infrared imaging has mainly three benefits. Firstly, being a non-contact approach makes it safe for facility members. They do not need to touch the power equipment to determine the temperature differences, whether in average condition or not.
Secondly, the facility members may use infrared cameras as visual evidence for documenting the intensity of the power failures. A visual image of the target area produced through the thermal scanners is like a smartphone photograph.
Thirdly, infrared imaging is done on a real-time basis. Meaning that the feature of video capturing through these cameras allow the service professionals to see and find the real problem of heating under various scenarios, like when it is in operating mode or does it heats up when it is switched off. The infrared camera offers the user to observe the real cause behind the rapid temperature changes, and that particular part is moving very fast..
Commonly Inspected Components
It has been found that the leading cause of overheating is associated with disproportionate current and high resistance. Infrared imaging enables you to see these heat signatures, which causes impending damage to electrical systems. Typically, the current which flows through an electric circuit, gets converted into heat energy. Whenever there is an abnormal flow of charge, it results in high heat generation, potentially damaging the entire distribution network.
A thermal imager offers you to see these heat signatures followed by abnormal heating long before and prevent electrical systems from exploding as a result.
Important Safety Considerations
Infrared inspection of electrical installations can bring occupational hazards to maintenance professionals. Only qualified and experienced staff should do infrared scanning from a safe distance. The methods involve taking images of active equipment that can trigger an arc-flash while opening the enclosures. The high-temperature explosion occurs through various electrical defects. The maintenance staff should not go beyond the flash protection boundary, a distance in which staff should wear the right protective gear to scan the faulty factor.
Another vital point to keep in mind is the need to deploy the right people in the right place. Meaning that if one person is qualified enough to do the infrared scanning, he may not qualify enough to open the covers. Similarly, a person may be qualified to access the equipment but may not have the same qualifications to do an infrared inspection.
Besides the above two points to consider while infrared scanning, one should consider the other two hazards during the inspections:
- Electrical shocks–Electrical shocks are another occupational hazard that needs to be taken seriously, specifically when you are being exposed to open electrical equipment and panels. Infrared imaging may not pose any severe threat directly. It involves non-contactable measurement with the electrical equipment, but current and voltage reading may cause shock hazards if not dealt with measures.
- Safe work planning–Before the inspection process, safe work planning is needed and followed strictly. Apart from the electrical risks involved, one needs to be aware of the potential hazards to access restricted areas.
Infrared Inspection and Testing Procedures
At the time of infrared scanning electrical components, equipment, and other electrical systems, it should be completed under the standard operating rules, and to see the problem without the covers, though in line with the safety methods.
Power connections and the path responsible for the flow of excessive current is at high risk for causing abnormal heat, which is the primary source behind electrical failures. Lack of proper balance beyond the usual heating of power units and phases are easily detected through infrared scanners.
You may often find the temperature difference is not a dependable indicator of the problem, since many factors may cause a surge in the temperature. Problems are sometimes overlooked when the temperature of a power part shoots-up. Therefore, it is necessary to note down the loading conditions at the time of measurement.
Importance of Visual Inspections
The natural sense of smell and eyesight may offer the required information which is not easily detected through imaging device’s electrical fluctuations. Before inspecting the electrical equipment, a visual check is done to search for problems related to overheating, such as faulty wired insulation or damaged conductors.
Conclusion
Maintaining electrical systems through the ideal use of thermal imaging plays a crucial part in the smooth functioning of massive electrical systems. Before they turn too risky, identifying potential problems can prevent electrical distribution systems posing severe threats to staff and infrastructure. Costly equipment and breakdowns are also prevented if thermal scanning is done, and preemptive maintenance is carried out regularly.
The infrared scanners can give you false positives, both in the analysis stage and image collection stage, if the maintenance people are not careful. This is because electrical equipment may always remain hot since thermal scanners have an extraordinary ability to pick up those hot-spots instantly. Therefore, it is of prime importance to understand that there are various factors on which the measurements are dependent.
In the end, infrared scanning is a mixture of useful diagnostic tools and a well-qualified thermal imager, which helps in the reduction of equipment breakdowns and the most incredible value in electrical preventive maintenance.
