Method for performing nondestructive detection on distribution transformer winding material with two ends heated

Abstract

The invention discloses a method for performing nondestructive detection on a distribution transformer winding material with two ends heated. The method comprises the following steps: S1, connecting the two ends of a to-be-detected winding with a conducting rod respectively through copper bar connecting wires; S2, fixedly arranging a heating module on the conducting rod; S3, controlling heating ofthe heating module to heat the conducting rod at the two ends of the winding consistently; S4, connecting a thermoelectric potential measuring instrument with the conducting rod through a thermoelectric potential measuring wire and acquiring thermoelectric potential Ev of the whole distribution transformer; and S5, performing detection judgment on the material of the to-be-detected winding according to the thermoelectric potential Ev acquired by the thermoelectric potential measuring instrument. The method has the following beneficial effects: the two ends of the winding are heated simultaneously and the heating temperature is maintained to be the same, so that thermoelectric potential error generated at the connection position of the thermoelectric potential measuring wire (wire clip) and the conducting rod during thermoelectric potential measurement is avoided, and the winding material is accurately distinguished to be copper or aluminum under the condition of not damaging the distribution transformer winding.

Description

technical field [0001] The invention relates to the technical field of distribution transformers, in particular to a method for non-destructive testing of winding materials of distribution transformers heated at both ends. Background technique [0002] Distribution transformers use copper windings, which is the requirement of power companies and many power users, but some unscrupulous merchants do not hesitate to use transformers made of aluminum windings in order to maximize their profits. This kind of "aluminum instead of copper" transformer makes power users buy counterfeit aluminum wire transformers at the price of pure copper wires, and also suffers economic losses. On the other hand, the quality of aluminum wire transformers produced by such manufacturers is also difficult to guarantee, which brings potential safety hazards. [0003] In recent years, the existence of distribution transformers with aluminum windings has also been found during random inspections of dist...

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Problems solved by technology

[0005] The first is to carry out X-ray flaw detection and industrial radiographic film photography on the transformer windings, and compare the photographed results with normal copper winding transformers to confirm the material of the windings. convenient;

[0006] The second detection method is to measure the time-resistance curve of the distribution transformer winding under a fixed current, and then compare it with the time-resistance curve of copper and the time-resistance curve of aluminum. For details, please refer to the application number 200810158124.7 named "Transformer Winding wire material tester and its test method” Chinese invention patent, but this detection method is less accurate when used on site, and is greatly disturbed by winding material, thickness and other factors;

[0007] The third method is non-destructive testing of transformer winding materials based on thermoelectric potential. This method has high reliability. For details, please refer to the Chinese utility model patent titled "An Intelligent Diagnosis Device for Transformer Winding Material" with the application number 201620701836.9. The theoretical research of this method Accurate and reliable, but in the actual application process, it is found that after the winding end is heated, a certain thermoelectric potential will also be generated between the terminal copper bar and the thermoelectric potential measurement clamp, which makes the patent unable to accurately measure the thermoelectric potential at the winding junction

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