1 Overview

Shanghai Dafan supplies frequency-modulated series resonance testing. The variable frequency series resonance 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-piece 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 DFVF3000 series resonance withstand voltage equipment for withstand voltage testing. Shanghai Dafan ranks among the top three in the variable frequency series resonance equipment industry.



2 Applicability

The variable frequency series resonance withstand voltage test device, portable frequency-modulated series resonance test, is mainly used for the following aspects: 1. AC withstand voltage testing of 6kV-500kV high-voltage cross-linked cables 2. Power frequency withstand voltage testing of 6kV-500kV transformers 3. AC withstand voltage testing of GIS and SF6 switches 4. AC withstand voltage testing of generators 5. AC withstand voltage testing of other high-voltage power equipment such as busbars, bushings, and instrument transformers. The variable frequency series resonance test device is widely used in power, metallurgy, petroleum, chemical, and other industries, suitable for acceptance and preventive testing 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-piece 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 resonance test device (volume and weight are about 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.



Aliases:



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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 of 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 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 object voltage 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 higher test voltage on the test object CX.