Analysis on Commutation Failure and DC Differential Protection Unwanted Action of Yunnan-Guangdong UHVDC

• Published in: Applied Mechanics and Materials Vol. 446-447; no. Advanced Research in Material Science and Mechanical Engineering; pp. 784 - 789
• Main Authors: Xie, Hui Fan, Chen, Yan Zhou, Feng, Dong, Wang, Qi, Yang, Guang Yuan, Chen, Xiao Peng, Peng, Guang Qiang
• Format: Journal Article
• Language: English
• Published: Zurich Trans Tech Publications Ltd 01.11.2013
• Subjects: Bridges (structures); Commutation; Direct current; Failure analysis; High voltages; Low pass filters; Low voltage; Outages; Yunnan-Guangdong UHVDC; Commutation Failure (CF); DC Differential Current; CT Characteristics; DC Differential Protection
• ISBN: 9783037859087; 3037859083
• ISSN: 1660-9336; 1662-7482; 1662-7482
• DOI: 10.4028/www.scientific.net/AMM.446-447.784

In order to reveal the commutation failure process and the reason for DC differential protection (87DCM) unwanted action of Yunnan-Guangdong UHVDC in 9.12th 2012, and to lessen the unnecessary outage and guarantee a safe and stable operation, the 9.12 outage is deeply studied, including commutation failure phenomena and equivalent circuit analysis, high voltage DC current, low voltage DC current and their differential current analysis and reason for 87DCM unwanted action, and the final conclusions come out that: (1) 9.12 commutation failure includes V1 failing to communicate to V3 of Y bridge and V2 failing to communicate to V4 of D bridge; (2) during commutation failure process, high voltage DC current and low voltage DC current all raise rapidly and both contain DC component, AC component and no-circle rising component, and theoretically high voltage DC current equals to low voltage DC current; (3) failure in low pass filter circuit of pole 1 low voltage CT leads to measuring differential current between high voltage and low voltage DC current, and finally leads to unwanted action of 87DCM.