Adaptive protection schemes of Distributed Generation at distribution network for automatic reclosing and voltage sags

In this paper, the adaptive protection schemes of utility interconnected distributed generation (DG) units for distribution automatic reclosing and voltage sag are proposed. Based on the general transient responses of DG units with synchronous generator during a fault by the reclosing types, i.e. radial reclosing and passive reclosing, classifying algorithms of reclosing types with varying fault resistance are proposed. Also, mathematical formulation of adaptive protection coordination schemes for reclosing types and voltage sags are introduced. The proposed algorithms are evaluated by the case study using PSCAD/EMTDC simulation tool.