GE Multilin G60 Generator Management Relay 5-1455 SETTINGS 5.5 GROUPED ELEMENTS5STAGE 1 SETTINGS:The stage 1 characteristic is typically set to detect a loss of excitation for load conditions of 30% of the nominal or higher.This is achieved with a mho element with a diameter equal to the base impedance of the machine and an offset equal tohalf the machine transient reactance (X′d).(EQ 5.32)The stage 1 element should be time delayed to allow for blocking by the VT fuse failure element (50 ms).STAGE 2 SETTINGS:The stage 2 characteristic is typically set to detect a loss of excitation for all load conditions. This is achieved with a mhoelement with a diameter equal to the synchronous reactance of the machine and an offset equal to half the machine tran-sient reactance (X′d).(EQ 5.33)During stable power swing conditions the positive-sequence impedance may momentarily enter the stage 2 characteristic.For security of the function under such conditions, it is recommended to delay stage 2 by a minimum of 0.5 seconds.The LOSS OF EXCIT BLK setting specifies a FlexLogic™ operand for blocking the feature based on user-programmable con-ditions. When the blocking input is asserted, the element resets its timers, de-asserts the PKP and OP operands (ifasserted), clears self-reset targets, logs a ‘blocked’ event if events are enabled, and becomes inactive. When unblocked,the element will start functioning instantly. If exposed to pickup conditions for an extended period of time and unblocked, theelement will pickup and start timing out at the moment of unblocking.The element responds to the positive sequence impedance as shown below.Figure 5–86: LOSS OF EXCITATION SCHEME LOGICCENTER 1 Zb X′d+2-----------------------, RADIUS 1 Zb2-------= =CENTER 2 Xd X′d+2-----------------------, RADIUS 1 Xd2-------= =LOSS OF EXCITATIONFUNCTION:LOSS EXCIT BLK:SETTINGSETTINGGenerator=1, Motor=1Disabled=0SETTINGEnabled=0Disabled=1LOSS OF EXCITATIONSOURCE:SETTINGI_1V_1Off=0830001AB.CDRLOSS OF EXCITATIONCENTER 1:LOSS OF EXCITATIONFUNCTION:LOSS OF EXCITATIONCENTER 2:LOSS OF EXCITATIONPKP DELAY 1:LOSS OF EXCITATIONPKP DELAY 2:LOSS OF EXCITATIONRADIUS 1:LOSS OF EXCITATIONRADIUS 2:RUNRUNORORSETTINGSSETTINGSETTINGFLEXLOGIC OPERANDSFLEXLOGIC OPERANDSFLEXLOGIC OPERANDFLEXLOGIC OPERANDFLEXLOGIC OPERANDFLEXLOGIC OPERANDFLEXLOGIC OPERANDLOSS EXCIT STG1 PKPLOSS EXCIT STG2 PKPLOSS EXCIT STG1 DPOLOSS EXCIT STG2 DPOLOSS EXCIT STG1 OPLOSS EXCIT STG2 OPLOSS EXCIT OPLOSS EXCIT PKPLOSS EXCIT DPO0 ms20 ms0 ms0 ms20 ms 0 msI_1 > 0.05 puBLOCK (See description)RUNCOMPARATORRUNSETTINGLOSS OF EXCITATION UVSUPV 2 :SETTINGEnabled=0Disabled=1LOSS OF EXCITATIONUV SUPV :LOSS OF EXCITATION UVSUPV 1 :ORORAND|V_1| < PICKUP AND
