Adaptive functions in G0> and YY0 earth fault protection

Abstract

In this paper, the benefits resulting from the application of YY0 and G0> earth fault protection with adaptive functions − limiting the risk of outsiders being shocked and reducing the likelihood of two-phase short-circuiting with the ground, are presented. The possibilities of improving the effectiveness of admittance protection by introducing special adaptive functions in control algorithms of station automation and decision algorithms of YY0 and G0> criteria are shown. The rules for using such functions have been described and it has been shown that they have a very significant impact on improvement the effectiveness of protection system. It can be stated that in typical medium voltage networks and solutions of active adaptive functions, good conditions are obtained for the operation of admittance protections even at several times higher resistances in the place of earth fault than when these functions are deactivated or not implemented.