Method for diagnosing power transformer winding working condition

Abstract

The invention relates to a method for diagnosing power transformer winding working condition. The method includes the following steps: (1) inputting a signal Vi to a vibration generator to conduct vibration excitation to a power transformer winding, and collecting and recording a vibration signal Voi of each measuring point according to N vibration acceleration sensors on the surface of the power transformer winding; (2), respectively conducting Fourier transform to the input signal Vi and the vibration signal Voi of each measuring point, and then obtaining a vibration frequency response curve H(omega) of the power transformer winding; (3) conducting the Fourier transform to the vibration frequency response curve H(omega) and then obtaining a free vibration signal H(t) of the power transformer winding; (4) decomposing the free vibration signal H(t) into a plurality of natural mode functions; (5) conducting Hilbert transform to all natural mode functions which are obtained by decomposing; (6) constructing an analytic signal; (7) obtaining a kth natural frequency of the power transformer winding; (8) conducting discrimination to the power transformer winding working condition according to the changing of the natural frequency. Compared with the prior art, the method has the advantages of being precise in diagnosis, convenient to operate, safe and the like.

Description

technical field [0001] The invention relates to a diagnostic method based on signal monitoring, in particular to a diagnostic method for the working state of a power transformer winding. Background technique [0002] The transformer is one of the most important equipment in the power system, and its operation stability has a great influence on the safety of the power system. With the increasing capacity of my country's power grid, the short-circuit capacity is also increasing. The huge electromagnetic force generated by the surge current formed by the short-circuit of the transformer outlet poses a serious threat to the mechanical strength and dynamic stability of the transformer winding. At present, the operating environment of substation equipment and lines is not optimistic. The deformation caused by the impact of external short circuit on transformer winding is a relatively common fault in the process of transformer operation, which poses a great threat to the safe opera...

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Problems solved by technology

[0016] The test sensitivity of the frequency response method is higher than that of the short-circuit impedance method. However, due to the complexity of the frequency response waveform, the judgment of the winding condition requires more experience, and it is difficult to form a clear quantitative criterion. Therefore, no criterion has been formed so far.

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