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Abroad explores a few kinds of methods of transformer winding displacement
From;    Author:Stand originally
The displacement of exploration transformer winding, can analyse transformer state and serviceability. The method of displacement of winding of foreign exploration transformer is: Impedance change measures a way, low-pressure concussion experiments; Frequency answers analytic way; Stray loss frequency answers a way; Transfer function law. In these measurement technique, impedance measures law and fundamental is the magnetoresistive when measuring winding to be out of shape and impedance, after be out of shape for winding, magnetoresistive is out of shape, impedance also produces change subsequently. Low-pressure concussion experiment measures a course to carry the displacement condition with winding of transformer of short circuit around very effective, because it can have the finger mark of transfer function contrast. Frequency answers a way is a kind of the most commonly used method, the frequency after it is out of shape through comparative winding is answered undertake judging. The change of eddy current loss that the advanced point that stray loss frequency responds a way is pair of winding is very sensitive. This kind of method can explore the hidden trouble that insulation exists, these hidden trouble can cause winding a place a certain number of shunt-wound lead short circuit, and can cause lead eddy current loss increase.

In high-pressured transformer substation, use stray loss frequency to answer a way but after transformer of easy test and verify endures short circuit the state of its winding, and can regard monitoring transformer as a kind of method of ageing. The different point that stray loss frequency responds law and impedance to measure a way is, the frequency range that its measure is in 20 ~ 600Hz, include industrial frequency. 

Stray loss frequency answers a law to measure voltage of the Rms electric current of every kinds of frequency, Rms and power of have rendered great service, this kind of method can undertake according to measuring impedance to change transformer is diagnosed. The slight axial displacement that although use impedance to measure law and stray loss frequency to answer a law to all can explore winding,appears, but the axial displacement of exploration winding of a kind of method after using should measure a way than impedance more effective. Stray loss frequency answers a law to measure a curve to undertake explanatory judging according to contrast, can measure a result to undertake contrast according to similar same transformer, the same table transformer that also can pass according to previous trial undertakes contrast.

To three-phase transformer, but according to transformer 3 phasic the measurement between undertakes contrast as a result. The difference of stray loss existence that because center pillar winding is mixed,upright ministry circles across block. The influence of these difference ascribe gasoline tank. Gasoline tank affects each to 3 phasic stray loss not identical. Be not all and additional loss to all appear in gasoline tank, but distortion meets the leakage magnetic flux that gasoline tank causes produce higher eddy current loss in lead or other structure. Below this kind of circumstance, undertake contrast with similar transformer or the best kind that with the same station that has had a test before transformer has contrast general is exploration winding displacement. For example, use stray loss frequency to answer a law to measure a transformer phasic the difference of eddy current loss between is 40% . After the experiment ends, disassemble instantly winding. Although did not discover winding is out of shape, but the curve that stray loss frequency answers a law to be measured makes clear, the coating burn that bedding face of existence of photograph of 2 winding A accumulates, b there is 8 turns occurrence short circuit in shunt-wound lead.
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