In an alternating electric field, the dipole moment generated by dielectric polarization will change direction as the direction of the electric field changes, and the charged particles or polar molecules that constitute the dipole moment must move in position or direction of rotation accordingly. This movement or rotation will interact with the surrounding material – it needs to overcome the friction with the surrounding material to do work and generate heat.
This part of the electrical energy lost to heat the dielectric is called dielectric loss. Dielectric losses occur regardless of whether it is a DC electric field or an AC electric field. Under a DC electric field, it mainly manifests as conductance loss, caused by leakage conduction current. In the alternating electric field, in addition to the losses caused by leakage conduction current, the dielectric also has losses caused by alternating polarization and losses caused by uneven structure. Due to frequent changes in the alternating electric field, the polarization loss of the dielectric is generally larger than the leakage conduction loss, which is usually expressed by the loss tangent, Tan Delta.
According to the loss formation mechanism, Tan Delta of dielectric loss is mainly divided into the following types:
1) Conductivity loss
3) Ionization loss
4) Structural loss
For insulating materials or dielectric materials used in capacitors, large Tan Delta of dielectric losses not only cause the dielectric material itself to heat up and affect its performance, but also accelerate material aging and reduce material life. Therefore, the smaller the requirement, the better.There comes the meaning of Tan Delta Tester.
Tan Delta Tester
The Tan Delta Tester is an automated instrument that measures the dielectric loss tangent (Tan Delta) and capacitance value (Cx). It can measure the dielectric loss tangent (Tan Delta) and capacitance value (Cx) of various insulating materials, insulating sleeves, power cables, capacitors, mutual inductors, transformers and other high-voltage equipment on site under power frequency and high voltage.
Features of Tan Delta Tester
Voltage range: 0 – 60 kv peak
Frequency range: 0.01 Hz – 0.2 Hz
Full report generating software
Displayed data: loss angle, voltage, current, & frequency
Accuracy +/- 2% + 0.005
Insulating Oil Dielectric Loss Tester / Tan Oil Delta Tester is a new generation fully automatic insulating oil loss and resistance tester ,transformer Tan Delta Oil Analysis,designed according to ASTM D924 and GB/5654. It is used to measure dielectric dissipation factor and DC resistance of insulating oil and others. insulating fluids. Easy to use with reliable and accurate test data.
Experiment procedure of Tan Delta Test
1. The surface of the inspection sample should be clean, smooth, and free of cracks, bubbles, impurities, etc. The surface of the sample should be scrubbed with a cloth dipped in absolute ethanol.
2. Adjust the instrument according to the operating procedures of the Q table, select the measurement frequency, and measure the values of C1 and Q1.
3. Put the sample into the test electrode, and adjust the capacitor C to make the circuit resonate and reach the maximum Q value. Record the values of the tuning capacitance C2 and Q2.
4. The sample should be conditioned at standard laboratory temperature and humidity for at least 24 hours.
3. Take out the sample from the test electrode, adjust the distance of C or the test electrode to make the circuit resonate again, write down the corrected capacitance value and Q value of C or the test electrode, Beijing Zhide Innovation Testing Instrument will calculate it based on the test value. Find the loss angle tanδ and dielectric constant ε.
4. Other high-frequency testing instruments are operated according to their instructions. The testing instruments calculate the loss angle tanδ and dielectric constant ε based on the test values.
5. When there are special requirements for sample processing, it can be carried out according to the product standards.