Industrial frequency resonance transformer

Abstract

The invention relates to a transformer capable of realizing resonance in industrial frequency under the condition of no mechanical governor mechanism. The technical scheme adopted by the invention is as follows: the transformer comprises an excitation transformer, a rectifier connected with the excitation transformer, an isolation transformer and a controller, wherein the isolation transformer is used to ensure that the excitation transformer and the controller realize high potential isolation; after detecting the collected currents on primary side and secondary side of the isolation transformer and the output current of the rectifier, the controller adjusts the AC excitation impedance of the excitation transformer through DC magnetic bias to form resonance with the impedance of a test. On one side, the industrial frequency resonance transformer can form resonance in industrial frequency, output industrial frequency test voltage, have the same working frequency with the device to be tested and effectively detect the insulation defect of the device to be tested; on the other side, the transformer has the advantages of no moving part, low noise and non-maintaining; and furthermore, the variable-frequency power source with large capacity is not needed, the cost is reduced and the failure rate is low.

Description

technical field [0001] The invention belongs to the field of high-voltage tests, and relates to a power-frequency resonant transformer for power-frequency withstand voltage tests for large-capacitance power equipment. Background technique [0002] When the high-voltage power equipment is in the factory test and the acceptance test after the on-site installation is completed, the power frequency withstand voltage test must be carried out to verify whether the insulation is reliable. Due to the high test voltage, the test current will be very large for power equipment with large ground capacitance, such as power capacitors, cables, SF6 combined electrical appliances, etc., so the test power supply capacity required is also large, which makes it impossible to use ordinary test transformers. Meet the requirements, especially when the test is carried out at the installation site of the equipment, the problem is more prominent. [0003] Since the equipment under test is equivalen...

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Problems solved by technology

[0018] For the resonant transformer with mechanically adjusted air gap, since the electromotive force of the iron core is very large when the reactor is working, especially in the case of large capacity, the resonant transformer with mechanically adjusted inductance has the disadvantages of high noise and unreliable mechanical life.

For the frequency conversion resonant transformer, although the mechanical moving parts are removed, its equivalence will be affected because the frequency of the test power source deviates from the actual operating frequency of the equipment under test, and the cost of the high-power variable frequency power supply will also make the resonant transformer The total cost is greatly increased

[0019] The difficulty in solving the above problems lies in whether the inductance can be continuously and accurately adjusted under static and power frequency conditions.

So far, the improvement of the resonant transformer is mainly on the basis of mechanical tuning, how to reduce noise and improve life through fine machining and better mechanical adjustment mechanism, and frequency conversion tuning is a major improvement measure to achieve static tuning, but its The adverse effect is that the test frequency deviates from the power frequency, which makes the equivalence of the test worse

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