Research on turn-to-turn short-circuit faults and short-circuit harmonic characteristics of current transformers

Turn-to-turn short-circuit faults in current transformers (CTs) exert profound impacts on power system stability and protective relay operations. This paper presents a comprehensive investigation into the characteristics of turn-to-turn short-circuit faults and their harmonic current distribution patterns. The study first establishes the CT current transfer function through theoretical derivation, followed by detailed analyses of its amplitude-frequency and phase-frequency characteristics under normal operating conditions. To systematically evaluate fault behaviors, turn-to-turn short circuits are categorized into mid-winding and terminal-winding configurations, with comparative simulations conducted to reveal their distinct operational impacts. Mechanistic interpretations are provided to explain the observed discrepancies in fault manifestations. Furthermore, the research systematically examines the harmonic current transfer characteristics across varying short-circuit turn ratios, revealing significant variations in harmonic propagation patterns. The findings provide valuable insights into CTs transient behavior and harmonic transfer mechanisms, offering critical references for power system protection design and fault diagnosis methodologies.