On-line monitoring method for vibration and noise of AC power transformer influenced by DC magnetic biasing

Abstract

The present invention relates to a method for on-line monitoring the vibration and noise of the alternating-current power transformer which is affected by the direct-current magnetic biasing, and the method belongs to the electric power safety monitoring technique in the electric field, and the method comprises the following steps: when the direct-current magnetic biasing does not exist collecting the noise acoustic pressure signal of the noise sound pressure meter at the transformer position to confirm the vibration signal monitoring point, and recording the principal character data of vibration of transformer body when no direct-current magnetic biasing exists at the monitoring point; when the direct-current magnetic biasing state appears executing on-line monitoring according to the sampling interval, sampling frequency and monitoring period, and setting the monitoring threshold value of the maximum vibration amplitude; after each monitoring period analyzing the preserved raw data, when the early warning state appears steadily for more than one day continuously, the transformer body is needed to be further detected, otherwise, the operation state of the transformer is taken for excellent; the invention can realize the judgment to the vibration state of the transformer at the state of direct-current magnetic biasing and guarantee the safe and stable operation of the power transformer through long-period on-line monitoring.

Description

technical field [0001] The invention belongs to the electric power safety monitoring technology in the field of electric engineering, and in particular relates to a method for monitoring the operating state of an AC power transformer affected by DC bias magnetism by monitoring the surface vibration and noise state of a power transformer box body. Background technique [0002] The power transformer is the core equipment in the AC power system, and its core excitation characteristic curve presents a typical nonlinear. Under normal conditions, the transformer mainly operates near the saturation point of the characteristic curve, but under the influence of the single-pole return current of the DC system, part of the DC current flowing into the ground will flow into the AC grounded at the neutral point near the DC grounding pole. In the power transformer, the inflowing DC current can reach tens of amperes, and the DC magnetic flux component will appear in the transformer iron cor...

AI Technical Summary

Problems solved by technology

However, it can only realize the monitoring of noise sound pressure waveform and vibration amplitude in a short period of time. It is not consistent in time, lacks an intuitive description of vibration waveform, and cannot realize simultaneous monitoring and comparison of noise and vibration. To judge the change of the vibration spectrum, it is impossible to judge the vibration state of the transformer under the condition of DC bias magnetic field through long-term online monitoring

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