Influence of DC Bias and Remnant Flux on Measuring Current Transformers

Abstract:

Current transformer (CT) is an important transmission equipment in power systems. DC bias and remnant flux can change the working point of CT in the core magnetization curve and has a direct impact on the accuracy of electric energy metering and measurement. The simulation circuit model is built by using the simulation software PSCAD and the change of ratio error, phase displacement and exciting current with DC bias and remnant flux are analyzed. The results show that DC bias and remnant flux will both increase the ratio error and phase displacement in opposite directions and the error size will be far more than the limit value when DC bias and remnant flux exist in same direction at the same time. Furthermore, the existence of DC bias and remnant flux will also cause the raise of exciting current size, asymmetry of exciting current waveform and appearance of even harmonics. This will seriously affect the transmission accuracy of measuring CT.

• Periodical: Advanced Materials Research (Volumes 765-767)
• Pages: 2268-2271
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.765-767.2268
• Online since: September 2013
• Authors: Lu Shen, Shu Tao Zhao, Pei Zhang, Bin Hu, Xiao Qian Tian
• Keywords: DC Bias, Measuring Current Transformer, Phase Displacement, Ratio Error, Remnant Flux

References

[1] Lilai CHEN. Electric Power Automation Equipment, 2011, 31(1): 138-141. In Chinese.

[2] Yingbin CUI, Zhenyu TAN, Qingmin LI. Electric Power Automation Equipment, 2010, 34(23): 87-91. In Chinese.

[3] Kappenman J G, Albertson V D, Mohan N. IEEE Trans. on Power Apparatus and Systems, 1981, 100(3): 1078-1088.

DOI: 10.1109/tpas.1981.316574

[4] Changyun LI, Qingmin LI, Zhen LI. Proceedings of the CSEE, 2010, 25(19): 127-132. In Chinese.

[5] Chunlai LI, Xiaoyu TANG, Yean HUANG. Electric Power Automation Equipment, 2011, 31(7): 143-149. In Chinese.