New Method to Identify CT Saturation Based on EMD

Abstract:

Aiming at the problem that Current Transformer (CT) affects differential protection, this paper proposes a new method to identify CT saturation based on Empirical Mode Decomposition (EMD). Differential current can be decomposed into few Intrinsic Mode Functions (IMFs) by EMD. When CT is linear transfer, the current waveform is nearly a sine wave, and it only contains one dominant IMF. However, CT saturation leads to the distortion of secondary current which contains at least two dominant IMFs. From the defined projection area on t-axis of each IMF and the specific gravity coefficient, the number of dominant IMF can be got. Thus CT saturation can be identified. Theoretical analysis and simulation results show that this method can identify CT saturation of different degree. It is convenient to achieve and hardly to be affect by aperiodic component.

• Periodical: Advanced Materials Research (Volume 721)
• Pages: 488-491
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.721.488
• Online since: July 2013
• Authors: Wen Hua Xia, Mao Fa Gong, Guo Liang Li, Jian Yu Zhang, Xin Cheng
• Keywords: CT Saturation, Differential Protection, Empirical Mode Decomposition (EMD), IMF

References

[1] SHEN Quan-rong, YAN Wei. Asynchronous method for the recognition of current transformer saturation and its application, Automation of Electric Power Systems, vol 29, pp.84-86, 2005.

[2] HUANG Zhiyuan, HE Benteng, ZHANG Xuesong. Research on the practicality of current transformer saturation detection using the magnetic restraint principle, Automation of Electric Power Systems, vol 30, pp.75-79, 2006.

[3] ZHAO Yongbin, LU Yuping. An asynchronous method based saturation criterion for CT in busbar protection, Power System Technology, vol 30, pp.86-90, 2006.

[4] Kang Yongcheol, Ok S H, S K Kang. A CT simulation detection algorithm, IEEE Trans. on Power Delivery, vol 19, pp.78-85, 2004.

DOI: 10.1109/tpwrd.2003.820200

[5] LIAN De-qiang, WANG Jian-fei, CHEN B in, et al. A method for CT saturation detection based on wavelet theory, Huadian Technology, vol 32, pp.18-20,67,77, 2010.

[6] Luo Weiqiang, Bian Tie. One New Scheme to Discriminate Inrush Current from Internal Fault of Power Transformer Based on EMD Decomposition, Electric Power Science and Engineering, vol 25, pp.1-5, 19, 2009.