Abstract

Power transformers play an important role in the safe and reliable operation of the whole power grid. Once a fault occurs, it will endanger the normal operation of the transformer, and even result in power grid accidents. Accurate and practical methods of transformer fault monitoring and type identification have attracted extensive attention in the field of electrical engineering. However, it is difficult to obtain a large number of measurement data for different fault types on a large power transformer. The vibroacoustic characteristics of transformer faults have significant asymmetry. For the power transformer in service, it is complex and uneconomic to obtain the vibroacoustic signals under different fault conditions. To handle this problem, this paper proposes simulation methods of several common transformer core faults, based on multi-physical field coupling, and then analyzes the vibroacoustic signals generated by the operating transformer. Finally, it verifies the results of acoustic and vibration signals under several faults, through physical experiments. The results show that the transformer fault simulation method is reasonable and accurate. Furthermore, a change in the transformer core state will cause a change in the transformer vibroacoustic characteristics, and different types of core faults can be distinguished by the analysis of vibroacoustic characteristics.

Highlights

  • The iron core of the transformer plays the role of transmitting and converting electromagnetic energy

  • In addition to the prediction and diagnosis of the transformer operation state through vibration and noise, Tang D. proposed a power transformer fault diagnosis method based on an improved probabilistic neural network (PNN)

  • Based on the coupling of multi-physical fields, a set of simulation methods for common power transformer core faults are proposed in this paper

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Summary

Introduction

The iron core of the transformer plays the role of transmitting and converting electromagnetic energy. The accompanying sound and vibration signals during transformer operation will change due to the change in the mechanical state of the iron core These asymmetric effects can be used as fault indicators of power transformers. Experimental and theoretical studies of interlaminar eddy current loss in laminated cores were carried out by Shah Sahas B. et al [14] Among these contributions, the researchers mostly studied the thermal effect caused by the interlaminar insulation fault, but paid little attention to the change in vibroacoustic characteristics. On one hand, the eddy current caused by interlaminar insulation faults will affect the magnetic field distribution in the transformer core, resulting in a change in electromagnetic force. Based on the coupling of multi-physical fields, a set of simulation methods for common power transformer core faults are proposed in this paper. The simulation model adopted to analyze the vibroacoustic characteristics of the model transformer, using COMSOL5.3 Multiphysics software, is developed

Simulation of Core Looseness Fault
Simulation of Multipoint Grounding Fault in
Experiment Verification of Core Fault Simulation Method
Comparison of Vibroacoustic Characteristics of Transformer under Fault Conditions
Conclusions
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