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Shanghai Wangxu Electric Co., Ltd
Previously, the high-voltage dielectric loss tester achieved dielectric loss detection in this way
Date: 2021-06-28Read: 10
The high-voltage dielectric loss tester is a new type of digital measuring instrument for automatic measurement of dielectric loss factor and capacitance. It is an integrated structure with a built-in dielectric loss testing bridge and a variable frequency voltage regulating power supply. By adopting variable frequency power supply technology and utilizing single-chip microcontrollers and electronic technology for automatic frequency conversion, analog-to-digital conversion, and data computation, the system achieves strong anti-interference ability, fast testing speed, high accuracy, and easy operation.
Under the action of AC voltage, the dielectric consumes some electrical energy, which will be converted into thermal energy and result in losses. This type of energy loss is called dielectric loss. When an AC voltage is applied to a dielectric, there exists a phase angle difference between the voltage and current in the dielectric. The residual angle δ of PSI is called the dielectric loss angle, and the tangent tg δ of δ is called the dielectric loss angle tangent. The TG δ value is a parameter used to measure the dielectric loss. The instrument measurement circuit includes a standard circuit (Cn) and a test circuit (Cx).
The standard circuit consists of a built-in high stability standard capacitor and a measurement circuit, while the test circuit consists of the test sample and the measurement circuit. The measurement line consists of a sampling resistor, a preamplifier, and an A/D converter. By measuring the standard circuit current and the amplitude and phase of the tested circuit current separately, the capacitance value and dielectric loss tangent value of the test sample can be obtained through vector operation using a digital real-time acquisition method by a microcontroller.
Precautions for Testing High Voltage Dielectric Loss Tester Device:
1. When using the high-voltage dielectric loss tester device, the grounding terminal of the instrument must be reliably grounded. Turn on the power, the instrument first performs a self-test (display screen, photoelectric communication, memory, operation keys, digital to analog conversion, grid frequency), and after passing the self-test, enters the main directory. ）
2. During the testing process, it is strictly prohibited to operate the "test voltage" selection switch. After entering the measurement mode, users can use the "stop" button to exit the measurement mode at any time.
3. When using, the insulation condition of the test sample should be measured first (usually measured with a megohmmeter,>1000 megameters).
4. Select the test voltage level based on the withstand voltage level of the test sample. (Use 10KV gear when higher than 10KV)
5. Only when the instrument power is turned off or the test voltage selection switch is placed in the "off" position, is it considered safe to contact the rear of the instrument and its measuring cable with the test sample.
6. When using the positive wiring method, the UH terminal outputs high voltage, while using the negative wiring method, the Cx terminal outputs high voltage.
7. Special insulated cables can be used for mopping. When the electrical capacity is less than 1000PF, the measuring cable on the high-voltage side should be suspended to ensure the accuracy of the test.
8. Do not replace fuse tubes that do not meet the panel indication values.
9. When using the high-voltage dielectric loss tester device, do not replace the testing cable provided by the manufacturer at will to ensure the accuracy of the measurement.
