1 Overview

Shanghai Dafan supplies frequency-tuned series resonant testing. The variable frequency series resonant withstand voltage test device is the newest type of AC withstand voltage test equipment designed based on the principle of series resonance. Traditional power frequency withstand voltage devices often have large single-unit volume, heavy weight, are inconvenient for on-site handling, and are not easy to combine arbitrarily, resulting in poor flexibility. Currently, a better method is to use Shanghai Dafan's DFVF3000 series resonant withstand voltage equipment for withstand voltage tests. Shanghai Dafan ranks among the top three in the variable frequency series resonant equipment industry.



2 Applicability

The variable frequency series resonant withstand voltage test device, portable frequency-tuned series resonant test, is mainly used for the following aspects: 1. AC withstand voltage tests for 6kV-500kV high-voltage cross-linked cables; 2. Power frequency withstand voltage tests for 6kV-500kV transformers; 3. AC withstand voltage tests for GIS and SF6 switches; 4. AC withstand voltage tests for generators; 5. AC withstand voltage tests for other high-voltage power equipment such as busbars, bushings, and instrument transformers. The variable frequency series resonant test device is widely used in industries such as power, metallurgy, petroleum, and chemicals, and is suitable for handover and preventive tests of capacitive test objects with large capacity and high voltage.



3 Product Analysis

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 (AC withstand voltage test transformers) often have large single-unit volume, heavy weight, are inconvenient for on-site handling, and are not easy to combine arbitrarily, resulting in poor flexibility. In comparison, the variable frequency series resonant test device (with volume and weight approximately 1/10 to 1/30 of traditional test transformers) is small in size, light in weight, easy to move, and is designed in a modular manner, making it convenient to flexibly configure the number of reactors according to on-site needs, greatly reducing labor intensity and improving work efficiency.



Other names:



Variable frequency resonant device, series resonance, variable frequency series resonant AC withstand voltage test device, variable frequency series resonance, frequency-tuned series resonance, series resonant withstand voltage test device, series resonant test equipment, cable withstand voltage test device, power frequency withstand voltage test device, cable AC withstand voltage test equipment, AC withstand voltage test device, frequency-tuned series resonant AC withstand voltage test device, variable frequency resonance, variable frequency series resonant resonance test device, variable frequency resonant withstand voltage device, series harmonic test device, series harmonic withstand voltage device, GIS AC withstand voltage test device, generator withstand voltage test device, variable frequency resonant withstand voltage test device, etc.



Principle:



We know that when the circuit frequency f=1/2π√LC, the circuit resonates, and at this time, the voltage on the test object is Q times the output voltage at the high-voltage end of the excitation transformer. Q is the quality factor of the system, i.e., the voltage resonance multiple, generally ranging from tens to over a hundred. First, adjust the output frequency of the variable frequency power supply to cause series resonance in the circuit, then, under the condition of circuit resonance, adjust the output voltage of the variable frequency power supply so that the voltage on the test object reaches 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.