Intelligent test method for DC resistance and DC demagnetization of 500kv transformer

Abstract

The invention discloses a 500KV transformer direct-current resistance and direct-current demagnetization intelligent test instrument comprising a rectifier circuit, a polarity-adjustable circuit, an inverter circuit, a constant current source module, a DSP control module, a standard sampling resistor, an AD data collector, a microprocessor used for controlling a display to display, and the display. The rectifier circuit, the polarity-adjustable circuit, the inverter circuit, the DSP control module and the constant current source module are connected sequentially. The standard sampling resistor is connected between the DSP control module and the constant current source module. The AD data collector, the microprocessor and the display are connected sequentially. The rectifier circuit is connected with the display. By adopting the instrument of the invention, single-phase and three-phase direct-current resistance test is realized, and the direct-current test time of transformer direct-current resistance test is shortened. Because the instrument is integrated with a direct-current demagnetization function, direct-current resistance test can be carried out at high current, and the test time can be shortened. Demagnetization is carried out in a timely manner after test, so that a large amount of detachment and installation time is saved, and the work efficiency is improved.

Description

technical field [0001] The invention relates to the field of transformer DC resistance testing, in particular to a 500KV transformer DC resistance and DC demagnetization intelligent tester and method. Background technique [0002] Some existing DC resistance testers in the industry do not have the function of DC demagnetization. During the test, a large current cannot be used to test the DC resistance. The test time is long, and the demagnetization cannot be performed in time after the test. The residual magnetism endangers the normal use of the equipment. [0003] When the prior art DC resistance tester tests the DC resistance of the three-phase transformer, the test method of the single-phase measurement mode is used to test the resistances of the transformers AN, BN, and CN respectively, and the test current flows from A, B, and C to the N phase. The lead resistance of the neutral point N to the resistance of each winding can be accurately tested. However, when using the...

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Problems solved by technology

However, when using the method of three-phase simultaneous measurement, the test current of the instrument flows from A and C to B, and the neutral point N does not flow through the current, so the resistance of the transformers AN, BN, and CN measured by the instrument does not include The contact resistance of the neutral point lead is

Therefore, the AN (BN, CN) resistance must be measured by a single-phase measurement method before the three-channel direct resistance test, which is inconvenient and inefficient. Moreover, it is impossible to use a larger current for the DC resistance test in the existing DC resistance test. It takes a long time to demagnetize in time after the test

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