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Table 57:PPLPHIZ Non group settings (basic)Name Values (Range) Unit Step Default DescriptionGlobalBaseSel 1 - 6 - 1 1 Selection of one of the Global Base Valuegroups6.6.6 Operation principle6.6.6.1 Operation principlePhase preference logic PPLPHIZ has 10 operation modes, which can be set by theparameter OperMode. The different modes and their explanation are shown in table 58below. The difference between cyclic and acyclic operation can be explained by thefollowing example. Assume a A fault on one line and a C fault on another line. ForOperMode = 1231c the line with C fault will be tripped (C before A) while for OperMode= 123a the line with A 1 fault will be tripped (A before C).Table 58:Operation modes for Phase preference logicOperMode DescriptionNo filter No filter, phase-to-phase measuring loops are not blocked during single phase-to-ground faults. Tripping is allowed without any particular phase preference at cross-country faultsNo pref No preference, trip is blocked during single phase-to-ground faults, trip is allowedwithout any particular phase preference at cross-country fault1231 c Cyclic 1231c; A before B before C before C1321 c Cyclic 1321c; A before C before B before A123 a Acyclic 123a; A before B beforeC132 a Acyclic 132a;A before C beforeB213 a Acyclic 213a; B before A before C231 a Acyclic 231a; B before C beforeA312 a Acyclic 312a; C before B beforeA321 a Acyclic 321a; C before B before AThe function can be divided into two parts; one labeled voltage and current discriminationand the second one labeled phase preference evaluation, see figure 81.The aim with the voltage and current discrimination part is to discriminate faulty phasesand to determine if there is a cross-country fault. If cross-country fault is detected, aninternal signal “Detected cross-country fault” is created and sent to the phase preferencepart to be used in the evaluation process for determining the condition for trip.Section 6 1MRK 506 335-UUS AImpedance protection172Technical manual