Open AccessNew protection scheme for power transformer based on superimposed differential current
Author(s) -
Shah Ashesh M.,
Bhalja Bhavesh R.,
Patel Rajesh M.
Publication year - 2018
Publication title -
iet generation, transmission and distribution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 110
eISSN - 1751-8695
pISSN - 1751-8687
DOI - 10.1049/iet-gtd.2018.0296
Subject(s) - inrush current , transformer , engineering , transmission line , differential protection , linear variable differential transformer , control theory (sociology) , current transformer , electronic engineering , computer science , voltage , distribution transformer , electrical engineering , artificial intelligence , control (management)
This study presents a new power transformer protection scheme based on extraction of positive and negative sequence components of superimposed differential currents. Different types of internal faults, magnetising inrush, and over‐excitation conditions have been generated by modelling in service power transformer of power transmission system of India using PSCAD/EMTDC software package. The simulation results clearly indicate the efficacy of the proposed scheme in detecting different types of internal faults like turn‐to‐turn, inter‐winding, line‐to‐ground, line‐to‐line, and line‐to‐line‐to‐ground. Together, the proposed scheme is competent to achieve effective discrimination between various external events (over‐excitation condition and various magnetising inrushes) and internal faults. Moreover, it provides equally promising results during current transformer (CT) saturation condition as well as for different connection and rating of the power transformer. Further, it remains stable during errors in the CT and tap change condition. Additionally, authenticity of the proposed scheme has been evaluated using internal fault and magnetising inrush data recorded in the real field. At the end, comparative assessment of the proposed scheme with the existing and conventional techniques clearly indicate its superiority in terms of better sensitivity for internal faults and higher stability during external events.