GE Multilin G30 Generator Protection System 5-1855 SETTINGS 5.6 GROUPED ELEMENTS5• NEG SEQ DIR OC1 FWD PICKUP: This setting defines the pickup level for the overcurrent unit in the forward direc-tion. Upon NEG SEQ DIR OC1 TYPE selection, this pickup threshold applies to zero- or negative-sequence current. Whenselecting this setting it must be kept in mind that the design uses a positive-sequence restraint technique.• NEG SEQ DIR OC1 REV LIMIT ANGLE: This setting defines a symmetrical (in both directions from the ECA) limitangle for the reverse direction.• NEG SEQ DIR OC1 REV PICKUP: This setting defines the pickup level for the overcurrent unit in the reverse direc-tion. Upon NEG SEQ DIR OC1 TYPE selection, this pickup threshold applies to zero- or negative-sequence current. Whenselecting this setting it must be kept in mind that the design uses a positive-sequence restraint technique.Figure 5–73: NEGATIVE SEQUENCE DIRECTIONAL OC1 SCHEME LOGIC827091A7.CDRANDANDANDANDANDORORNOTE:V_2 is negative-sequence voltageI_2 is negative-sequence currentI_0 is zero-sequence currentANDSETTINGOff = 0BlockSETTING= Neg Sequence= Zero SequenceTypeSETTINGSForward PickupRUN( |3I_0| – × |I_1| ) PickupK ≥Positive-Sequence RestraintTIMER1.25 cycles1.5 cyclesFLEXLOGIC OPERANDNEG SEQ DIR OC1 FWDSETTINGEnabled = 1FunctionACTUAL VALUESV_2I_2I_0RUN( |I_2| – × |I_1| ) PickupK ≥Voltage PolarizationSETTINGSForward ECARUNForward Limit AngleReverse Limit AngleOffsetForwardReverseSETTINGSReverse PickupRUN( |I_2| – × |I_1| ) PickupK ≥Pos Seq RestraintRUN( |3I_0| – × |I_1| ) PickupK ≥ANDANDANDFLEXLOGIC OPERANDNEG SEQ DIR OC1 REV
