The complete set of frequency conversion series resonance test equipment is a specialized high-voltage test device that utilizes the series resonance principle of inductance (L) and capacitance (C), adjusts the power frequency to cause resonance in the circuit, and generates high voltage on the test object, but greatly reduces the required power capacity. It is a key equipment for conducting AC withstand voltage tests on large capacity, high-voltage electrical equipment (such as cables, GIS, generators, transformers, etc.) in the power industry.
The complete set of frequency conversion series resonance test equipment is an indispensable testing method for daily electrical equipment debugging work. The circuit of the frequency conversion series resonance test equipment has been well used in voltage withstand tests of electrical equipment such as transformers and power cables. This article mainly introduces the practical application of the complete set of circuit for frequency conversion series resonance test.
(1) At present, more and more XLPE-XLPE insulated power cables are replacing the original oil filled paper insulated power cables for AC withstand voltage testing of power cables both domestically and internationally. However, there are many problems with the traditional cross-linked polyethylene cable DC withstand voltage test; Due to the large capacitance testing of cross-linked cables, the use of series resonance testing method is simple and convenient, and can obtain good AC voltage frequency and waveform. It has become an ideal testing method for AC withstand voltage testing of cross-linked cables.
(2) The AC withstand voltage test for power transformers, reactors, and transformers is clearly defined in the world, which can be carried out using power frequency voltage test or induced voltage test methods. The test voltage waveform should be as close to sine as possible. According to this standard, the circuit of the entire frequency conversion series resonance test device can complete the test under any conditions. The device has a wide frequency and voltage range, strong adaptability to the tested object, and can be used in conjunction with test objects of various voltage levels.
(3) The AC withstand voltage test of SF6 closed type combiner is an important method for checking the main insulation of GIS when SF6 is closed. In most cases, a series resonance testing device is used.
(4) The AC withstand voltage test for other equipment, such as circuit breakers and bushings, generally requires the withstand voltage test to be a power frequency voltage test. If the power frequency test device cannot meet the on-site requirements, the resonant withstand voltage test method can also be used as a substitute. When using the resonant withstand voltage test, due to the small capacitance of the device, the test frequency is high. However, the series resonant test device can also use appropriate compensation capacitors to reduce the test frequency, so that the instrument can reach a test frequency close to the power frequency.