The variable frequency dielectric loss tester, also known as the variable frequency dielectric loss tester, is a high-precision instrument for fully automatic measurement of dielectric loss tangent and capacitance of various high-voltage power equipment at power plants, substations, and other field sites. Due to the adoption of frequency conversion technology, accurate measurement can be ensured under strong electric field interference. The instrument is operated with a Chinese menu, and the microcomputer automatically completes the entire measurement process. This instrument is also suitable for measuring the tgδ and capacitance of high-voltage electrical equipment in workshops, laboratories, and scientific research institutions.

The instrument can measure high-voltage electrical equipment that is ungrounded or directly grounded using the positive and reverse wiring methods. It can also measure the tgδ of capacitive voltage transformers and the capacitance of main capacitors C1 and C2.

The instrument is equipped with a high-voltage step-up transformer and safety protection measures such as zero-crossing closing and lightning protection. During the test, high voltages of different levels from 0.5KV to 10kV are output, making operation simple and safe.

Tester Features




◆ Simple operation, Chinese display, printing

◆ Convenient use, no conversion needed

◆ The variable frequency dielectric loss tester comes with its own high voltage, strong anti-interference capability, and short test time.

Tester Characteristics




Tester Parameters























1. Due to the adoption of frequency conversion technology, accurate measurement can be ensured under strong electric field interference.
2. The instrument is operated with a Chinese menu, and the microcomputer automatically completes the entire measurement process.
3、 This instrument is also suitable for measuring the tgδ and capacitance of high-voltage electrical equipment in workshops, laboratories, and scientific research institutions; it also has the advantages of convenience, simplicity, and accuracy for loss testing of insulating oil.
4、 The instrument can measure high-voltage electrical equipment that is ungrounded or directly grounded using the positive and reverse wiring methods. It can also measure the tgδ of capacitive voltage transformers and the capacitance of main capacitors C1 and C2.
5、 The instrument is equipped with a high-voltage step-up transformer and safety protection measures such as zero-crossing closing and lightning protection. During the test, high voltages of different levels from 0.5KV to 10kV are output, making operation simple and safe.





1. High voltage output: 0.5 to 10kV, with each step increasing by 500V, a total of 20 steps

High voltage output cable, can be used dragged on the ground

Three frequencies: 45Hz, 50Hz, 55Hz

2. Capacity: 1500VA

3. Accuracy: tgδ: ±(reading*1.0%+0.08%)

Cx: ±(reading*1.5%+5PF)

4. Resolution: tgδ: 0.01% Cx: 1pF

5. Measurement range: 0.1% < tgδ < 50%

3PF< Cx < 60000PF

At 10KV, Cx ≤30000PF

At 5KV, Cx ≤60000PF

6. Power supply: AC 220V ±10% 50 ±1Hz

7. Harmonic adaptation: ≤3%

8. Operating conditions: -15℃-50℃ relative humidity <80%

9. Dimensions: 460 (L) ×335 (W) ×340 (H)

10. Weight: 30 kg

Working principle:

After the variable frequency dielectric loss tester starts measurement, the high voltage setting value is sent to the variable frequency power supply. The variable frequency power supply uses a PID algorithm to slowly adjust the output to the set value. The measurement circuit sends the actual measured high voltage to the variable frequency power supply, fine-tunes the low voltage, and achieves accurate high voltage output. According to the positive/reverse wiring settings, the measurement circuit automatically selects the input and switches the range based on the test current. The measurement circuit uses Fourier transform to filter out interference, separates the fundamental wave of the signal, performs vector operations on the standard current and the test current, calculates the capacitance from the amplitude, and calculates tgδ from the phase difference. Multiple measurements are repeated, and a middle result is selected after sorting. After the measurement is completed, the measurement circuit sends a voltage reduction command, and the variable frequency power supply slowly reduces the voltage to 0.