By sion932 
In the power system, the “health status” of equipment is directly related to the stable operation of the entire power grid. Just like our regular physical examinations, electrical equipment also needs to be “examined”, and the automatic dielectric loss tester is the indispensable “health examiner”. But what exactly does it do? How is it possible to achieve such precise ‘diagnosis’? Today, let’s unveil its mysterious veil together.
What is dielectric loss? Why is it so important?
Before delving deeper into the testing equipment, let’s first talk about “dielectric loss”. Simply put, when current passes through an insulating medium (such as transformer oil, cable insulation layer, etc.), due to the fact that the medium itself is not an ideal insulator, there will always be a portion of electrical energy converted into heat energy that is lost, and this energy loss is called dielectric loss.
What are the “culprits” that affect dielectric loss?
The magnitude of dielectric loss is closely related to many factors:
Temperature: An increase in temperature usually leads to intensified molecular motion in the medium, changes in dielectric constant, and thus increases dielectric loss.
Humidity: Moisture is the “enemy” of insulation materials. The entry of moisture can greatly increase dielectric loss and may lead to insulation breakdown.
The properties of insulation materials: Different insulation materials have different molecular structures and purities, and their inherent losses are also different.
Impurities: Free ions or polar impurities in insulating materials that accelerate movement and increase energy loss under the action of an electric field.
Aging degree: As the operating time increases, the insulation material will gradually age, its performance will decrease, and the dielectric loss will also increase accordingly.
Why pay attention to dielectric loss?
The value of dielectric loss is like a barometer for insulation materials.
Judging insulation performance: Low dielectric loss indicates good insulation material performance and low leakage current, which is an ideal state.
Early warning: If the dielectric loss value suddenly increases, it often indicates that the insulation material may have early faults such as moisture, deterioration, impurities or even partial discharge, which can buy us valuable repair time and avoid major equipment damage.
Guidance and maintenance: Through regular measurements, we can understand the operating trends of equipment and provide scientific basis for equipment maintenance and replacement.
What “tools” can we use to test?
Traditional dielectric loss testing methods often require manual operation, have low efficiency, and are easily affected by human factors. Modern automatic dielectric loss testers can greatly improve the accuracy and efficiency of testing.
our has a profound technical accumulation in this field. Its developed equipment can automatically complete the testing process, reduce operational steps, lower error rates, and provide detailed testing reports, providing strong support for the operation and maintenance of power equipment.
How does the automatic dielectric loss tester work?
Okay, now let’s talk about how this “automatic tester” works. Its core principle is actually the use of the method of “measuring capacitance and loss tangent”.
Applying voltage: The tester will apply an AC voltage to the insulation of the tested equipment (such as transformers, transformers, cables, etc.).
Measuring current: At the same time, it accurately measures the current flowing through the insulation. This current mainly consists of two parts: capacitive current (the current that exists mainly in ideal insulators) and leakage current (the current generated by dielectric loss).
Calculate the loss tangent: The precision circuit and algorithm inside the tester can separate the leakage current and combine it with the capacitance current to calculate the loss tangent value (tan δ). The tan δ value is a key indicator for measuring the magnitude of dielectric loss.
Automatic analysis and reporting: Modern automatic testers can also automatically analyze whether the tan δ value is within the normal range according to preset standards, and generate detailed test reports, visually displaying the “health status” of the equipment.
The benefits brought by automation
High precision: Automated equipment typically integrates high-precision measuring components and intelligent algorithms, which can reduce external interference and improve measurement accuracy.
High efficiency: One click operation, no need for tedious wiring and manual calculations, greatly reducing on-site testing time.
Reliability: reduces human operational errors, ensuring the stability and reliability of test results.
Data management: Many devices support data storage and export, facilitating subsequent device status tracking and analysis.
How can we do better? Make devices healthier and more sustainable
With advanced automatic dielectric loss testers, we can better safeguard the “health” of power equipment and ensure their long-term and stable operation.
Regular and standardized testing: Strictly follow the regulations and regularly use testing equipment to conduct “physical examinations” on key equipment.
Pay attention to abnormal data: Once an abnormal increase in tan δ value is found, it is necessary to immediately conduct in-depth investigation and analyze possible causes, such as moisture, pollution, aging, etc.
Combined with other testing methods: Dielectric loss testing is an important means of determining insulation condition, but it is not the only one. Combining partial discharge, DC withstand voltage and other tests can comprehensively evaluate the insulation performance of equipment.
Pay attention to environmental factors: Keep the operating environment of the equipment clean and dry, and avoid external factors affecting the insulation performance.
Technical cooperation: Professional manufacturers like our not only provide high-quality testing equipment, but also offer professional technical support and consulting services to users, helping us better master the use and maintenance skills of equipment.
Actual Case (Simplified Version)
A substation conducted a routine inspection on a transformer that has been in operation for many years. After using the automatic dielectric loss tester, it was found that the tan δ value of the high-voltage winding slightly increased. Although it was still within the allowable range, there was a clear trend compared to historical data. After further analysis, combined with other test results, it is determined that the insulation paper is affected by moisture due to the recent high environmental humidity. Timely measures were taken to dry the transformer, and after a period of time, the tan δ value was retested and returned to normal. The timely diagnosis and treatment this time effectively avoided potential insulation faults.
To safeguard the safety of the power grid
The automatic dielectric loss tester is not just a cold instrument, but also the “smart eye” that ensures the safe and stable operation of the power system. By understanding its working principle and application, we can more actively and scientifically manage and maintain power equipment, building a solid barrier for the electrical safety of thousands of households.
Frequently Asked Questions (FAQ)
Q: What power equipment can the automatic dielectric loss tester be used for? A: The automatic dielectric loss tester is widely used in various high-voltage electrical equipment, including but not limited to transformers, transformers, high-voltage cables, switchgear, insulators, etc., to evaluate their insulation performance.
Q: Why is dielectric loss an important indicator for measuring the quality of insulation materials? A: Dielectric loss directly reflects the energy loss of insulating materials under the action of an electric field. The lower the loss, the higher the purity, lower the degree of aging, and less moisture pollution of the insulation material, and the better its insulation performance.
Q: Are there any environmental requirements for dielectric loss testing? A: Yes, cleanliness and dryness of the testing environment are very important. If the testing site is damp, dusty or oily, it may affect the accuracy of the test results and even cause damage to the instrument itself.
Q: What is the measurement range of the automatic dielectric loss tester? A: Different devices have different measurement ranges, but generally speaking, they can accurately measure values ranging from very low tan δ values (such as 10 ⁻⁵ levels) to higher values. Specific parameters need to refer to the equipment manual.
Q: What should I do if the test results show high dielectric loss? A: High dielectric loss is usually a signal of decreased insulation performance. You need to analyze possible causes based on the device type and specific situation, combined with other test data, such as moisture, dirt, aging, internal defects, etc. When necessary, professional technicians or equipment manufacturers should be contacted for further diagnosis and treatment advice.