Cross‐voltage short‐circuit calculation for mixed‐voltage quadruple‐circuit lines on the same tower

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

“…Further, the PTPSC measured by 'PR3' can be obtained and then simplified into (7) based on (2), (3), (5)…”

“…Cross-voltage short-circuit faults can be classified into several types [5]: single-phase to single-phase cross-voltage faults, singlephase to two-phase cross-voltage faults, single-phase to three-phase cross-voltage faults, two-phase to two-phase cross-voltage faults etc.…”

“…Considering the L2C-L3bc fault (the cross-voltage non-ground fault between phase C of L2 and phases b and c of L3) as an example. According to the method of cross-voltage short-circuit calculation [5], the corresponding composite sequence network is shown in Fig. 2, where the subscripts 1, 2, and 0 are used to symbolise the positive, negative, and zero sequence components, respectively; E 1.A and E 1.a denote the pre-fault voltages of the fault nodes KI and KII, respectively; U k stands for the voltage of fault point after the fault occurs; ratio n t = U IB /U IIB , where U IB and U IIB are the reference voltage values of system I and system II, respectively.…”

“…At present, researches of the mixed-voltage quadruple-circuit transmission line system mainly focus on the short-circuit calculation of single-line faults or cross-voltage faults [5][6][7][8]. Analysis of the influence on relay protection caused by shortcircuit faults is relatively less [9][10][11], let alone the study of the effect on phase selectors.…”