Grounding Phase Determination in Non-Effective Grounding Systems in Case of Unsymmetrical Voltage
Xu Bo1, Zhang Jianwen1, Cai Xu1, 2, Guan Shanlian3, Yao Yong4
1. Key Laboratory of Control of Power Transmission and Transformation Shanghai Jiao Tong University Shanghai 200240 China 2. State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200240 China 3. Henan Electric Power Testing and Research Institute Zhengzhou 450052 China 4. Kaifeng Power Supply Company Kaifeng 475003 China
Abstract:When a single-line-to-ground fault happens in the power grid, it is complex and difficult to determine the ground phase especially in the case of an unsymmetrical voltage and a large transition resistance. And the unsymmetrical voltage is often ignored because of simplified analyses in the previous literature. In this paper, with these factors considered a detailed analysis of the single-line-to-ground fault and the phasor diagram of the line-to-neutral voltages are presented firstly. It is concluded that the trajectory of the neutral voltage is no longer a semi-circular, but a circular arc. What is worse, in some cases it is not suitable to apply the traditional criterions that the previous literature proposed. A new method of constructing three new “phase” vectors is presented to identify the ground phase. Theoretical analyses and simulations show that the method can overcome the shortcomings of traditional methods and determine the grounding phase accurately.
徐波, 张建文, 蔡旭, 管珊莲, 姚勇. 电网不对称条件下小电流接地系统接地相辨识[J]. 电工技术学报, 2011, 26(12): 175-182.
Xu Bo, Zhang Jianwen, Cai Xu, Guan Shanlian, Yao Yong. Grounding Phase Determination in Non-Effective Grounding Systems in Case of Unsymmetrical Voltage. Transactions of China Electrotechnical Society, 2011, 26(12): 175-182.
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