Adaptability of phase selectors based on phase‐to‐phase superimposed currents when confronting cross‐voltage faults in mixed‐voltage quadruple‐circuit line system

Abstract

For the mixed-voltage quadruple-circuit transmission lines on the same tower, its special construction form makes the cross-voltage faults, i.e. multi-circuit faults that occur between different voltage level systems, easy to occur. Although the phase selector based on phase-to-phase superimposed currents (PTPSC) shows excellent performance in the single transmission line, it cannot guarantee to identify faulted phases when confronting cross-voltage faults. In this study, the adaptability of phase selectors based on PTPSC is analysed and a new method of phase selection is put forward. First, the PTPSC measured by the relay can be obtained on the basis of cross-voltage short-circuit calculation. Then, the influencing factors and possible selection results are comprehensively analysed, and the corresponding measure has been proposed. Finally, a fault model of mixed-voltage quadruple-circuit transmission lines is constructed in PSCAD and simulation results agree well with the theoretical analysis, verifying the validity of this method.