The high-voltage withstand test of electrical equipment is one of the most important items specified in the Preventive Test of Insulation. The withstand voltage test can be classified into the AC withstand voltage test and the DC withstand voltage test. The AC withstand voltage test can also be divided into power frequency, frequency conversion and 0.1Hz ultra-low frequency test technologies. The 0.1Hz ultra-low frequency technology is the latest technology and is the technology recommended by IEC at present. The new generation series of ultra-low frequency high-voltage generators of our company are core products independently developed with the latest American technology. It adopts an 8-inch touch screen, the latest ARM7 single-chip microcomputer and a high-speed AD acquisition circuit, and it is equipped with background management software. It overcomes many shortcomings (see Table 1) of similar domestic products, and its cost performance is much higher than the similar imported products. It is particularly suitable for the withstand voltage test of electrical equipment (e.g.: power cables, power capacitors, large- and medium-sized generators and Motors, etc.) with large insulation equivalent capacitance, and it meets the requirements of the electric power industry standard General Technical Specification of Ultra-low Frequency High-voltage Generator DL/T849.4-2004 newly issued by the country in 2004.

1) Output rated voltage: see Table 3

2) Output frequency: 0.1 Hz, 0.05 Hz, and 0.02 Hz

3) Load capacity: 

0.1 Hz max. 1.1 µF

0.05 Hz max. 2.2 µF

0.02 Hz max. 5.5 µF

4) Measurement accuracy: 3%

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

6) Voltage waveform distortion: ≤5%

7) Service conditions: Indoors and outdoors; temperature: -10℃ ~ +40℃; humidity: ≤85％RH

8) Power fuse: see Table 3

9) Power supply: voltage 220 V ± 5%, 50 ± 5 Hz

Note: If a portable generator is used for power supply, the output voltage and frequency of the generator are required to be stable (generally it is required that power is greater than 3 kW, the frequency is 50 Hz, and the voltage is 220 V ± 5%

10) The capacitance of the tested product shall not exceed the maximum value for the rated capacitance of the instrument, and the values are shown in Table 3;

Table 3 Main Technical Parameters of Series Ultra-low Frequency High-voltage Generator