Mode Selection of Substation Small Resistance Earthing and Its Impact on Main Transformer Protection
Focusing on transforming substations'small resistance earthing systems,this essay analyzes,among the three modes of small resistance arrangement,the differences in requirement on zero-sequence current balancing for main trans-former(MF)differential protection,and the differences in current sensitivity excited by faults with various types,loca-tions,and source points.With respect to the wiring of multiple branch buses,it puts forward a new scheme which deploys independent earthing resistances for all the branch buses.This scheme,though requires additional equipment investment,facilitates system reliability improvement,waives the necessity of zero-sequence current balancing for MF differential pro-tection,and thereby results in unaffected sensitivity of relevant protections.
small resistance earthing systemzero-sequence current balancing of main transformer differential protectionprotection sensitivityproject investment comparison
万方数据
维普
