Studyonzero_sequencec_省略_sistanceGroundi.pdfVIP

2011The International Conference on Advanced Power System Automation and Protection Study on zero-sequence current distribution characteristics in Low Re- sistance Grounding mode 1* 1 1 1 HUANG JunKai , WU JiYang , WANG Gang , LI HaiFeng 1 South China University of Technology, Guangzhou 510641, China; Abstract: Low Resistance Grounding mode has been adopted in more and more megacities in China. The distribution charac- teristics of zero-sequence current in various cases of fault are fundamental for the proper operation of the zero-sequence cur- rent protection. Therefore, the distribution characteristics of zero-sequence current in the low resistance grounding mode are emphases of this paper. Based on Symmetrical Component Method, mathematical models and theory analysis were carried out for two-line single phase grounding fault of the same phase and of different phases. Thus, the mathematical expressions of ze- ro-sequence current were derived. On this basis, quantitative analysis and comparison to the distribution characteristics of ze- ro-sequence current in different cases were made summarizing the differences between single-line and multi-line where ground faults take place. Finally, based on PSCAD/EMTDC, a great deal of simulating calculation for different cases of fault was done in order to verify the correctness of our theoretical analysis. Keywords: low resistance grounding mode, multi-line single-phase-grounding fault, unbalanced fault 1 Introduction 2 Mathematical models