Heterodyne Anti-interference Dielectric Loss Tester
Darui Electric recommends:
The heterodyne fully automatic dielectric loss tester is a high-precision testing instrument used in power plants, substations, and other field or laboratory settings to test the dielectric loss tangent and capacitance of various high-voltage power equipment.The instrument features an integrated structure, incorporating a dielectric loss test bridge, variable frequency voltage regulating power supply, step-up transformer, and SF6 high-stability standard capacitor. The test high-voltage source is generated by the internal inverter and stepped up by the transformer for testing the test object. The frequency can be varied to 45Hz or 55Hz, 55Hz or 65Hz, using digital notch filtering technology to avoid interference from the power frequency electric field, fundamentally solving the problem of accurate measurement under strong electric field interference. It is also suitable for testing with generator power supply after a complete power outage. The instrument can be equipped with an insulating oil cup to test the dielectric loss of insulating oil.
Tester Features
◆ Simple operation, Chinese display, printing
◆ Convenient use, no conversion needed
◆ The heterodyne dielectric loss tester comes with built-in high voltage, strong anti-interference capability, and short test time.
Tester Characteristics
1. |
Due to the use of frequency conversion technology, accurate measurement can be ensured under strong electric field interference. |
2. |
The instrument uses a Chinese menu operation, 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 research institutions; it is more convenient, simple, and accurate for testing the loss of insulating oil. |
4、 |
The instrument can measure high-voltage electrical equipment that is ungrounded or directly grounded using positive or reverse connection 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 an internal high-voltage step-up transformer and incorporates safety protection measures such as zero-crossing closing and lightning protection. During the test, it outputs high voltages of different levels from 0.5KV to 10kV, making operation simple and safe. |
Tester Parameters
1、High voltage output: 0.5 ～10kV, each step increases by 500V, with a total of 20 steps
High voltage output cable, can be used dragging 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士10% 50士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 heterodyne dielectric loss tester starts the measurement, the high voltage set value is sent to the variable frequency power supply, which uses a PID algorithm to slowly adjust the output to the set value. The measurement circuit sends the actual high voltage to the variable frequency power supply, fine-tuning the low voltage to achieve accurate high voltage output. According to the positive/reverse connection setting, 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 object current, calculates capacitance from amplitude, and calculates tgδ from phase difference. Multiple measurements are repeated, and a median 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.
Note: The above information and technical parameters are compiled and published by Yangzhou Darui Electric Co., Ltd.
