The series variable frequency automatic resonance test device is mainly used for the variable frequency AC withstand voltage test of 10kV, 35kV, 110kV cross-linked rubber power cables, 66kV, 110kV, 220kV combination electrical appliances (GIS), and the power frequency AC withstand voltage test of hydraulic and thermal generators or power transformers. The device mainly consists of a variable frequency power supply, an excitation transformer, a fixed reactor, and a capacitive voltage divider.
Excitation Transformer
The insulation level of the excitation transformer determines the safe operation and insulation aging rate of the transformer. In order to achieve the durability of the excitation transformer and ensure that the potential rise during external flashover of the equipment endangers the main and longitudinal insulation of the intermediate transformer, end insulation is added to the winding paper at the first and last ends of the high-voltage output of the intermediate test transformer to evenly distribute the insulation turns between layers. In addition, the winding is a cylindrical winding, and the size of the capacitor is related to the area of the winding. When designing, it is intentional to make the area of the lowest and highest parts the same to improve the impact characteristics of the equipment. The winding barrel adopts a composite insulation tube: it can reduce local discharge and act as a barrier for the iron core. During the insulation treatment of the final assembly: Carefully follow the requirements of the operation manual for temperature, vacuum degree, and vacuum time curve rate, and use secondary vacuum equipment for treatment. The treatment process is rigorous to ensure good insulation level.
The transformer adopts enameled flat and round copper wire windings, oil immersed self cooling type, and iron shell structure; Static shielding layers are installed between the high and low voltage windings and the iron core, serving as both excitation and isolation transformers; A moisture absorber is installed on the upper part of the transformer. Having sufficient electrical and mechanical strength, necessary heat dissipation capacity, and margin for oil thermal expansion and contraction. The transformer is equipped with reliable lifting facilities. Spray orange red insulation paint on the shell. The structure and layout position of the components and parts of the transformer, such as bushings and valves, shall not hinder lifting, transportation, and fastening positioning during transportation. At the same time, there shall be sufficient electrical safety distance from the high-voltage and low-voltage bushings of the transformer, and no corona discharge shall be generated during use. Provide copper busbars for connecting the series parallel combination of high and low voltage windings of transformers for matching use. The transformer body is equipped with a hook that can bear the total weight of the transformer, making it convenient for on-site lifting. There are symmetrical arrangements on the cover plate of the transformer.
Distributed lifting rings facilitate core inspection during maintenance, and are equipped with corresponding lifting devices. The structure of the transformer is conducive to smooth transportation to the destination, and the accessories that need to be installed on site will immediately enter a continuous working state after installation.
The design and assembly of transformers and their accessories minimize vibration and can withstand the effects of transformer short-circuit electric force; The transformer core and larger metal structural components are reliably grounded through the oil tank, and there is a clear grounding symbol "┻" or "grounding" at the grounding point.
Wuhan UHV specializes in the production of series resonance (also known as variable frequency resonance test device), engaged in the electrical measurement industry for many years. Its products have first-class quality and welcome customers to come and purchase.