TDVLF Ultra-Low Frequency Generator Withstand Voltage Test Device

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Product Introduction

This product combines modern digital frequency conversion advanced technology, adopts microcomputer control, and fully automates boosting, bucking, measurement, and protection. Due to full electronic design, it is small in size and light in weight, with a large-screen LCD display that is clear and intuitive, and can display output waveforms and print test reports. The design indicators fully comply with the power industry standard "General Technical Conditions for Special Test Instruments for Power Equipment, Part 4: General Technical Conditions for Ultra-Low Frequency High Voltage Generators", and it is very convenient to use. Currently, domestic and foreign methods use mechanical modulation and demodulation to generate ultra-low frequency signals, so there are problems such as non-standard sine waveforms, large measurement errors, spark discharge in the high-voltage part, heavy equipment, and the need for high-power high-voltage resistors for discharge shaping in the second and fourth quadrants of the sine wave, resulting in high overall power consumption. This product overcomes these shortcomings and has the following features:

1, For rated voltage less than or equal to 50kV, the ultra-low frequency adopts a single-stage structure (one booster); for greater than 50kV, it adopts a series structure (two boosters in series), which greatly reduces the overall weight and enhances load capacity. Moreover, the two boosters can be used separately for low-voltage ultra-low frequency applications.

2, Current, voltage, and waveform data are directly sampled from the high-voltage side, ensuring data accuracy.

3, It has overvoltage protection function. When the output exceeds the set voltage limit, the instrument will stop protection, with an action time of less than 20ms.

4, It has overcurrent protection function: designed with dual protection for high and low voltage. The high-voltage side can accurately stop protection according to the set value; the low-voltage side will stop protection when the current exceeds the rated current, with an action time of less than 20ms.

5, The high-voltage output protection resistor is designed inside the booster, so no external protection resistor is needed.

6, Due to the use of high and low voltage closed-loop negative feedback control circuit, there is no capacitive rise effect in the output.

Technical Parameters

Output frequency: 0.1Hz, 0.05Hz, 0.02Hz

Load capacity: 0.1Hz   1.1μF

          0.05Hz  2.2μF

          0.02Hz  5.5μF

4. Measurement accuracy: 3%

5. Voltage positive and negative peak error: ≤3%

6. Voltage waveform distortion: ≤5%

7. Operating conditions: indoor and outdoor; temperature: -10°C to +40°C; humidity: ≤85% RH

Product Features

Ultra-low frequency insulation withstand voltage test is actually an alternative to power frequency withstand voltage test. We know that when performing power frequency withstand voltage tests on large generators, cables, and other test objects, due to their large capacitance in the insulation layer, a large-capacity test transformer or resonant transformer is required. Such huge equipment is not only heavy and expensive but also very inconvenient to use. To solve this contradiction, the power department adopted reducing the test frequency, thereby reducing the capacity of the test power supply. From years of theory and practice at home and abroad, it has been proven that using 0.1Hz ultra-low frequency withstand voltage test instead of power frequency withstand voltage test not only has the same equivalence but also greatly reduces the size and weight of the equipment. Theoretically, the capacity is about 1/500 of the power frequency, and the operation is simple, with more advantages than the power frequency test. This is why developed countries generally adopt this method. The National Development and Reform Commission has formulated the industry standard "35kV and below Cross-linked Polyethylene Insulated Power Cable Ultra-low Frequency (0.1Hz) Withstand Voltage Test Method". Our country is promoting this method, and this instrument is developed based on this need. It can be widely used in AC withstand voltage tests for cables and large high-voltage rotating motors.

Note: The above information and technical parameters are compiled and released by Yangzhou Dary Electric Co., Ltd.