Extension strategy for Bus-Bar Differential Protection in smart substation

In smart substation, intelligent primary equipment and electronic instrument transformer exchange information with bay-level device through optical fiber. Intuitive secondary circuits of relay protection have been changed into abstract data streams. During the extension, the influence of extended devices on the operating devices must be considered. In this paper, the extension strategy for 220kV Bus-Bar Differential Protection was proposed. Tripping tests and corresponding safety measures were applied to ensure the extension strategy. 220 kV Power-Factory Line I& II extension project in 220 kV Wenjin smart substation was sampled to prove the extension strategy, corresponding tripping tests and safety measures practical.