Thermal monitoring of electrical equipment is an effective way to identify defects in power equipment that are detected without shutting down the electrical installation. Special products called thermal imagers measure the temperature of the connections, which allows you to determine the degree of heating of the metal surface. In places of poor contact or integrity loss for a number of other reasons, it will be higher than usual. Identification of such problems allows you to eliminate the defective area in time, which will protect the equipment from more harmful damage and emergency outages.
Why spend?
Thermal imaging control of electrical equipment allows you to:
- Conduct operational monitoring of the state of power equipment, identify bottlenecks at various stages of development of defects.
- Carry out independent monitoring, which ensures compliance with measures and responsibilities to maintain the electrical installation in good condition. Actual for an external audit of consumer equipment.
- Ensure fire safety of electrical installations. During emergency situations, there is a risk of damage to other equipment due to fire. Acceptable for power transformers where oil can be emitted.
The main purpose is associated with the prevention of emergencies in the early stages of a defect.
Types of control
In modern practice, the following types of thermal imaging control of electrical equipment are used:
- Periodic. It is set by regulatory documents and involves the examination of power equipment in a timely manner.
- Current. It is aimed at identifying defects and malfunctions of a power plant before and after a major (current) repair.
- Emergency. Provides monitoring of the status of other equipment after an emergency.
This is the main gradation, which determines the time and place of specialized measurements.
Dates
The frequency of verification of thermal imaging control of electrical equipment is determined by regulatory documentation, including PTE, measurement and calculation methods, RD 34.45-51.300-97 (for Russia). The following recommendations are given in the documentation presented for conducting a survey of electrical installations:
- up to 35 kV - at least 1 time in 3 years;
- 110-220 kV - at least 1 time in 2 years;
- above 220 kV - annually.
There are exceptions that may be set by the chief engineer of an energy enterprise not lower than normative, as well as in the following cases:
- Before and after major or current repairs of the electrical installation.
- For newly introduced overhead lines after a year of operation.
- For electrical installations whose service life exceeded 25 years and when working out contact joints, at least 5%. A similar procedure should be carried out at least 1 time in 3 years.
- When operating power equipment with extreme current loads, where overload is possible, as well as in places with unfavorable physical or environmental conditions (ice, wind, fog) at least 1 time per year.
The technique of thermal imaging control of electrical equipment is the main document that should be guided by. Some equipment manufacturers recommend shortening the inspection interval. Some experts note that maintaining the network in working condition requires constant monitoring due to wear and tear. This practice cannot be implemented due to the volume of work.
Advantages and disadvantages
Thermal control of electrical equipment is accompanied by the following advantages:
- Portability, which allows inspection of any electrical installation.
- Increased measurement accuracy compared to a pyrometer or similar devices.
- Most models allow you to record the result, which is the basis for further decision making by the organization’s management.
- Identification of defective compounds at an early stage of their appearance, which prevents the development of accidents.
As for the shortcomings, they are insignificant and are expressed in ease of use and accuracy of measurements. Devices of individual manufacturers have large dimensions, where stands are not provided. On some models, low response of fixation.
Thermal imager
In fact, thermal imagers are an ordinary digital camera that uses special optics that can compare the temperature range. Due to the large area of coverage, the quality of the results obtained does not depend on the distance to the facility, which ensures the implementation of the procedure in the operational state of the power plant.
The main and most important element of any thermal imager is the focal matrix (FPA). The latter is highly sensitive, which ensures the accuracy of determining the level of heat generated. To work with a personal computer, cameras of this type received USB connectors. This ensures the preservation of the results of the examination, which confirms or refutes the need for service.
Cost of equipment
Thermal imaging control of electrical equipment is an expensive pleasure, since installations of this type cost an average of $ 300 for domestic use and about 3,000 for professional use. Considering several teams for the maintenance of high-voltage and distribution lines, as well as other electrical installations, a substantial amount is rushing. Nevertheless, such an acquisition pays off in full due to a decrease in network failure and energy shortages.
The price tag is largely determined by additional functionality, as well as the complexity of the matrix. Some products cost up to the mark of 25,000 dollars. Such equipment allows you to shoot from a distance of up to 500 meters, which is great for performing a survey of large overhead lines.
Verification and verification of the device
Functional testing of the device is carried out immediately before the inspection of the compounds. Norms of thermal imaging control of electrical equipment suggest the implementation of such actions before each temperature measurement. However, in practice such a process is not carried out.
As for the verification of the product - like any measuring device must pass within the time specified by the manufacturer. The device must have the CMS label, which confirms the accuracy of the measurement. Please note that the use of Chinese-made pyrometers often give an error and do not pass the test in metrology.
Practical applicability
The use of thermal imaging control of electrical equipment has proven itself on the positive side. This is due to the effectiveness of defect detection, safety and ease of implementation of tasks. Proper measurement involves:
- Checking the performance of the device by taking temperature measurements on the skin. There are other methods of verification operations.
- Installation of equipment on a special stand, which ensures maximum measurement accuracy. In practice, the presented stage is carried out with hands, which shows slight differences in the results.
- Direct the matrix directly to the electrical connections. With a weak lens, there are difficulties in fixing. It should be noted that some models do not reflect the temperature background when pointing the device to the paint.
- Record the result, and then transfer the information to a PC or laptop. The implementation of the presented operation is performed by standard methods using the USB-connector.
- Consider in detail the results obtained, write out a protocol, which is the final stage of thermal imaging control of electrical equipment.
Based on the documentation and control data, a decision is made on the criticality and the need to eliminate the defect.
Protocols
The thermal imaging control protocol for electrical equipment is a document of a local or state standard that reflects the main and important aspects of the study of electrical installations. Here an opinion is given regarding the examination, defects are recorded. If necessary, photographs are attached confirming the need for repair work. The standard form is presented in the appendix of administrative documentation 34.45-51.300-97.
Safety precautions
The RD “Thermovision control of electrical equipment” clearly spells out the safety measures that must be observed during the inspection. This includes:
- Employees who have been instructed, trained in safe work with the device, and also have fire safety skills are allowed to work independently with the thermal imager. During the examination, the use of work clothing is necessary.
- During a periodic or unscheduled inspection, it is forbidden to eliminate the identified defects. This type of work may be performed by order.
- It is forbidden to approach live parts closer than permissible norms. It must be remembered and understood that the installation is energized, which is an increased source of danger.
These are the main positions that determine the safe conduct of work. Sample conditions and requirements are presented for periodic inspections of electrical installations.
Conclusion
The thermal imager is a special device that has found wide application in the power industry. A product of this type is very expensive, but due to the purpose and efficiency of the tasks, it is an integral part of preventing accidents. The frequency of thermal imaging control of electrical equipment, as well as the methodology for performing the inspection, is prescribed in the regulatory documentation: in the rules of the operating technique, in RD 34.45-51.300-97.
Monitoring the condition of the connections is recorded in the protocol, on the basis of which the equipment should be taken out for repair. The need to eliminate such defects is determined by the chief engineer of the energy enterprise. The technology is life-saving for high-voltage networks, which reduces the accident rate by at least 70%. In most cases, the elimination of defects does not require extinction of the overhead line.
Contact research must be performed exactly with safety precautions. Note that thermal imagers have a much greater application. The device is used in construction, hunting, medicine and many other fields of activity.