An Improved Algorithm for Variable Slope Differential Protection of Distribution Transformer using Harmonic Restraint
International Journal of Electrical Energy
In the context of reliable protection of distribution transformer, differential protection is considered to be the best. The infiltration of Distributed Energy Resources into the grid has necessitated the security of transformer to be increased many fold. In this paper, an improved variable slope differential method is proposed for a 1 MVA, 11/0.433 kV /Y connected distribution transformer considering provision for accounting challenges of DES penetration. By using second and fifth harmonic
... raint, along with negative sequence component, it is possible to effectively differentiate between various conditions like inrush, over excitation and internal fault including inter turn fault with few shorted turns. Apart from these, cases for remanence and external fault are also taken up to test the reliability of the scheme. Effective simulation studies have been performed to demonstrate the efficiency of the proposed scheme using PSCAD/EMTDC.