Method and system for judging DC bias magnetic field of autotransformer whose neutral point is grounded by capacitor

Abstract

The present invention discloses a method and a system for direct current magnetic bias discrimination of an autotransformer having a neutral point with capacity ground. The method comprises the stepsof: detecting vibration signals for an autotransformer to be detected having a neutral point with capacity ground; performing spectral analysis of the vibration signals of the autotransformer to be detected, extracting 50Hz vibration signals and signal amplitudes of the harmonic frequency in a 2kHz range of the vibration signals, and calculating direct current magnetic bias vibration feature parameters; and inputting the direct current magnetic bias vibration feature parameters into a pre-trained machine learning classification model, and obtaining a current direct current magnetic bias stateof the autotransformer to be detected, wherein the machine learning classification model comprises a classification mapping relation of detecting the direct current magnetic bias vibration feature parameters of the autotransformer to be detected and detecting whether a direct current magnetic bias state is generated or not. The method and the system can effectively discriminate the direct currentmagnetic bias state of the autotransformer having the neutral point with capacity ground, cannot be influenced by outside environmental disturbance, and are high in detection safety and efficiency with no need for contacting with an electrification portion of a device.

Description

technical field [0001] The invention relates to the field of detecting the DC bias state of an autotransformer, in particular to a DC bias discrimination method and system for an autotransformer whose neutral point is grounded through a capacitor. Background technique [0002] When the UHVDC power transmission system operates in a single-pole ground loop mode or a bipolar unbalanced mode, a large amount of DC current will generate a potential difference on the ground path flowing through it. If the AC transformer is operated nearby, the DC current will pass through the neutral ground of the transformer. The path formed by the site and the transmission line flows through the transformer winding, resulting in a DC bias phenomenon. DC bias involves a large number of transformers, which can easily cause a series of problems such as increased noise and vibration of transformers, loosening of core clamps, loosening and deformation of windings, insulation damage, decline in short-c...

AI Technical Summary

Problems solved by technology

However, the uncertainty of noise signal detection is high, and the test results are easily disturbed by external environmental factors

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