5-188 M60 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUALGROUPED ELEMENTS CHAPTER 5: SETTINGS55.7.4 Stator differentialSETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) STATOR DIFFERENTIALThe stator differential protection element is intended for use on the stator windings of rotating machinery.Figure 5-99: Stator differential characteristicThis element has a dual slope characteristic. The main purpose of the percent-slope characteristic is to prevent amaloperation caused by unbalances between CTs during external faults. CT unbalances arise as a result of the followingfactors:• CT accuracy errors• CT saturation STATOR DIFFERENTIAL STATOR DIFFFUNCTION: DisabledRange: Disabled, Enabled STATOR DIFF LINEEND SOURCE: SRC 1Range: SRC 1, SRC 2, SRC 3, SRC 4 STATOR DIFF NEUTRALEND SOURCE: SRC 1Range: SRC 1, SRC 2, SRC 3, SRC 4 STATOR DIFFPICKUP: 0.100 puRange: 0.050 to 1.000 pu in steps of 0.001 STATOR DIFFSLOPE 1: 10 %Range: 1 to 100% in steps of 1 STATOR DIFFBREAK 1: 1.15 puRange: 1.00 to 1.50 pu in steps of 0.01 STATOR DIFFSLOPE 2: 80 %Range: 1 to 100% in steps of 1 STATOR DIFFBREAK 2: 8.00 puRange: 1.50 to 30.00 pu in steps of 0.01 STATOR DIFFBLK: OffRange: FlexLogic operand STATOR DIFFTARGET: Self-resetRange: Self-reset, Latched, Disabled STATOR DIFFEVENTS: DisabledRange: Disabled, EnableddifferentialrestrainingBreak 1Break 2PickupSlope 1Slope 2BlockOperate830735A1.CDR
