AUTHOR=Yonghao Huang , Shuheng Dan , Zhiyuan Liu 

TITLE=Study on the optimum value of remanent magnetism for suppressing ferromagnetic resonance of voltage transformer in all-cable line

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 12 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2024.1408924

DOI=10.3389/fenrg.2024.1408924

ISSN=2296-598X

ABSTRACT=With the increasing demand for safety and aesthetics in urban power grids, 10 kV cable lines are gradually becoming mainstream. However, this trend also brings new challenges. Cables can be equivalent to capacitors at industrial frequency, which are prone to resonate with the voltage transformer (PT) in the system, causing drastic changes in current and voltage waveforms and posing a threat to the stable operation of the system. In the actual power system, the intrusion of lightning waves into the substation will lead to different residual magnetism in the PT core, which further changes the core inductance value and affects the ferromagnetic resonance of the system to a certain extent. In order to study the effect of remanent magnetism on the ferromagnetic resonance of the system, this paper establishes a 10 kV cable line simulation model based on the PSCAD software, adopts the UMEC transformer which is able to simulate the saturation characteristics to construct the PT, and uses a DC current source to simulate the intruding current to generate remanent magnetism, so as to explore the effects of the remanent magnetism on the system's ferromagnetic resonance under different sizes and directions. The results show that when the remanent magnetization value is positive and less than 0.6 pu, it can effectively suppress the ferromagnetic resonance inrush current of the voltage transformer, and the smaller the value of remanent magnetization is, the better the suppression effect is; the negative remanent magnetization can not suppress the ferromagnetic resonance of the PT, and on the contrary, it may exacerbate the inrush current, which may lead to more serious consequences. This study helps to improve the stability of the power grid and provides a valuable reference for future grid design and maintenance.