Research on power transformer vibration and noise under DC bias condition

Author(s):  
Mengmeng Ai ◽  
Wenhui Liu ◽  
Yi Shan

In the process of Ultra high voltage direct current (UHVDC) transmission, the direct current (DC) bias of power transformer is easily induced, which makes the transformer exciting current distorted, the ferromagnetic material saturated and the magnetic leakage increased, and then leads to the increase of core vibration and noise. Aiming at this problem, taking a 240 MVA, 330 kV three-phase five-column power transformer as an example, the coupling of the electromagnetic field, structural force field and acoustic field is studied, and the influence of DC bias on vibration and noise of power transformer core is analyzed in this paper. According to the magnetic density and electric density of transformer core under different magnetic bias degree, the structural force field is solved, and the displacement and surface acceleration of core are obtained, which can be as the excitation of sound field to determine the noise distribution of transformer. In order to avoid the natural frequencies which easily cause resonance, the modal analysis is needed to obtain the natural frequencies and modal modes of the core. The transformer noise under no-load and DC bias conditions of the prototype is tested experimentally and compared with the theoretical calculation, the results prove the accuracy of the simulation calculation method in this paper.

2016 ◽  
Vol 50 (2) ◽  
pp. 297-309 ◽  
Author(s):  
Yongming Yang ◽  
Xingmou Liu ◽  
Fan Yang ◽  
Ammad Jadoon ◽  
Chenyang Zhang

2021 ◽  
Vol 257 ◽  
pp. 01038
Author(s):  
Weijian Peng ◽  
Qi Liu ◽  
Li Liang ◽  
Wenqi Jiang ◽  
Zhuoyuan Zhang

The converter transformer plays a critical role in the high-voltage direct current (HVDC) transmission system, which connects but separates the AC grids and the converter. This paper briefly introduced the essential design requirement of the HVDC converter transformer in a system at ±800kV level and analyzed the DC bias influence on the transformer. The DC bias current effect simulations are analyzed in MATLAB and ANSYS Maxwell in this paper, respectively.


2021 ◽  
Author(s):  
Ruifeng Zhan ◽  
Yuying Hu ◽  
Fan Li ◽  
Zhou Mi ◽  
Lingpeng Dong

With the rapid development of China’s electric power industry, the high-voltage and long-distance direct current (DC) transmission effectively solved the problem of uneven power distribution. When the high voltage direct current transmission is in unipolar operation or bipolar asymmetric operation, part of the DC current will flow into the transformer winding through the grounded neutral point, which will cause the DC bias problem. This article used CDEGS software for modeling, and introduced the process of CDEGS software for DC bias simulation modeling. In this paper, the DC bias model of regional power grid is first established, based on the Zhejiang power grid topology and the test soil resistivity date. Then the DC bias currents of the transformers are calculated, and finally the corresponding treatment measures are proposed. According to the governance measures, this article adjusted the simulation model. The calculation results show that the treatment measures have good effects, which can provide an important reference for the future treatment of transformer DC bias.


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