Extension strategy for 110kV Bus-Bar Differential Protection in smart substation

The intuitive secondary circuits of relay protection have been changed into abstract data streams in smart substation. Reasonable safety measures must be taken during the extension with the consideration of the influence of extended lines. Based on the analysis of maintenance mechanism for smart substation, the extension strategy for 110kV Bus-Bar Differential Protection and corresponding safety measures have been proposed and been proved practical by the 110 kV Xuelin Line I& II extension project in 220 kV Wenjin smart substation.