Method for identifying state of power transformer winding by using pseudorandom sequence

Abstract

The invention provides a method for identifying a state of a power transformer winding by using a pseudorandom sequence. The method comprises the following steps: adopting an M sequence in the pseudorandom sequence as a signal source; after exciting a winding system, collecting input and output signals by using double-channel digital collection equipment; calculating to obtain a pulse response transferring function of the winding system according to the input and output signals; then carrying out correlation function calculation on the input and output signals to obtain a pulse response of the winding system; then describing the state of the winding according to a derivation parameter and a frequency response curve; and judging whether the transformer winding is deformed or not. The testing method disclosed by the invention can be used for comparing amplitude-frequency response curves of the transformer winding and has the consistency. The method disclosed by the invention has the characteristics that the pulse response transferring function of the winding can be directly obtained, the measurement time is short and the like; and furthermore, the method disclosed by the invention can judge the state of the transformer winding according to the change of specific parameters, including poles, null points and the like, of the transferring function, so that the problem in the prior art that technicists easily carry out erroneous judgment is solved.

Description

technical field [0001] The invention belongs to the technical field of high voltage, and in particular relates to a method for identifying the winding state of a power transformer by using a pseudo-random sequence. Background technique [0002] With the continuous growth of the power grid, the short-circuit current and short-circuit capacity in the system increase, and the short-circuit faults of power transformers, reactors and other equipment in operation often occur, and their windings will also be more likely to encounter Deformation and other faults, the state of the winding, that is, whether the winding is deformed under the normal state, is a basic sign of the operating state of the transformer. The existing detection methods for transformer windings include short-circuit impedance method, low-voltage pulse method, frequency response method, etc. Among them, the short-circuit impedance method is relatively simple to operate, and there are molding equipment for field u...

AI Technical Summary

Problems solved by technology

[0003] However, there are still problems in the use of the frequency response method (FRA method): 1) When the signal source of the FRA test system outputs a single frequency, it generally outputs multiple cycles continuously, and uses the middle part of the excitation and response signals to analyze; then in the next frequency On-point test analysis; this leads to a long measurement time of the FRA method, which is not conducive to the rapid processing of data

Take up a lot of storage space

Moreover, for graphic data with small local differences, the same feature value and judgment can be obtained. If the small local differences reflect the winding status and trend, it may cause misjudgment and misjudgment. That is to say, analysis based on graphics technology less sensitive

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