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Variable Frequency Series Resonance Test
The variable frequency series resonance test is different from general-purpose testing instruments. Its biggest feature is that the same set of equipment can be used for AC withstand voltage tests of different electrical equipment, such as cross-linked cables, transformers, GIS, motors, and generators. In addition to the series of typical commonly used models provided in this selection catalog for users to choose from, it is usually necessary to design a configuration scheme based on the user's test object range and test requirements, to meet the test requirements of different regions, different users, and different test objects.
Various large power transformers, power cables, steam and hydro generators, and other capacitive equipment must undergo AC withstand voltage tests strictly according to test regulations on a regular basis. Under power frequency conditions, due to the large capacitance of the test object or the high test voltage requirements, the power supply capacity of the test device also has correspondingly high requirements. Traditional power frequency withstand voltage devices often have large single-piece volume, heavy weight, are not easy to transport on site, and are not easy to combine arbitrarily, resulting in poor flexibility. Currently, a better method is to use the series resonance method for withstand voltage testing.
We know that when the circuit frequency f=1/2π√LC, the circuit resonates. At this time, the voltage on the test object is Q times the output voltage of the high-voltage side of the excitation transformer. Q is the quality factor of the system, that is, the voltage resonance multiple, generally ranging from tens to over a hundred. First, adjust the output frequency of the variable frequency power supply to make the circuit resonate in series, then under the condition of circuit resonance, adjust the output voltage of the variable frequency power supply to make the test voltage on the test object reach the test value. Due to the resonance of the circuit, a relatively small output voltage from the variable frequency power supply can produce a high test voltage on the test object CX.
DFVF3000 variable frequency series resonance test is mainly used for:
1. AC withstand voltage test of 6kV-500kV high-voltage cross-linked cables
2. AC withstand voltage test of generators
3. AC withstand voltage test of GIS and SF6 switches
4. Power frequency withstand voltage test of 6kV-500kV transformers
5. AC withstand voltage test of other high-voltage power equipment such as busbars, bushings, and instrument transformers.
