Demagnetization and residual magnetism measurement device for power transformer

Abstract

The invention relates to a demagnetization and residual magnetism measurement device for a power transformer. The device comprises a demagnetization structure for performing demagnetization in a direct-current attenuation reversing mode, a residual magnetism measuring structure used for quantizing residual magnetism by collecting second harmonics in the exciting current, and a controller connectedwith the demagnetization structure and the residual magnetism measuring structure. The demagnetization and residual magnetism measurement device is advantaged in that on one hand, residual magnetismof the power transformer can be reduced or even eliminated, on the other hand, the residual magnetism amount of an iron core of the power transformer can be effectively measured before, during and after demagnetization, and the residual magnetism amount can be accurately reflected, the device has further has properties of simple operation, high demagnetization speed, obvious demagnetization effect, accurate and rapid residual magnetism amount test and the like.

Description

technical field [0001] The invention relates to the elimination of residual magnetism of a power transformer, in particular to a device for degaussing and residual magnetism measurement of a power transformer. Background technique [0002] The power transformer is one of the important components of the power grid, and plays an extremely important role in the safe and stable operation of the power grid. The residual magnetism will remain in the transformer iron core after operations such as transformation ratio test, DC resistance test and no-load test are performed on the power transformer. When the transformer is put into operation, the residual magnetism of the iron core saturates the iron core of the transformer for half a cycle, and a large number of harmonics are generated in the excitation current. This not only increases the reactive power loss of the transformer, but also may cause a malfunction of the relay protection device, resulting in certain economic losses. ...

AI Technical Summary

Problems solved by technology

This method is to verify whether the residual magnetism before and after degaussing has decreased through the comparison method, and does not quantify the residual magnetism

2. Quantify the residual magnetism by detecting the magnitude of the two harmonic components in the excitation current at the instant of transformer low voltage switching on. The disadvantage of this method is that it is greatly affected by the phase angle of the voltage when switching on. Effectively control the voltage phase angle of closing

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