Section 5 1MAC309294-MB FControl functions342 RER620Technical ManualThe condition for any source to be enabled in tie-point mode is to set the settings Vt lineenable and Vt load enable as TRUE and the respective source enable inputs should betriggered with a positive pulse.The source enable inputs S1_ENABLE and S2_ENABLE are pulse triggered inputs. Thisis true if the present status of source is enabled. By applying a positive pulse to therespective inputs the respective source will be disabled and vice versa.Phase status determinationPhase status determination module determines the status of phases selected. The status ofphase can be live or dead or neither live nor dead based on the level of the respective phasevoltages.The phase status logic compares the measured value of the respective phase voltage withLive bus threshold and Dead bus threshold settings. If the measured voltage is greater thanLive bus threshold for a time of Live bus time then the respective phase is declared as livebus. If the measured voltage is less than Dead bus threshold for a time of Dead bus timethen respective phase is declared as dead bus. If the measured voltage exceeds the Deadbus threshold for a time less than Volt regain time then it is ignored by the function anddead bus timer will be continuous during this time. If the voltage is restored for the Voltregain time or longer, the dead bus timer is cleared and the status will change to either livebus or neither live nor dead based on the voltage level. The phase is declared as neitherlive nor dead if the phase voltage is above the Dead bus threshold and below the Live busthreshold.In sectionalizing mode, if Vt config line is “3” and the setting Sect3POpMode is selectedas “Any phase” then any of the 3 phases should be declared as dead to activate theLCM_TRIP. If Sect3POpMode is selected as “Three phase” then all of the 3 phases shouldbe declared as dead to activate the LCM_TRIP. If Vt config line is “1” then the respectivephase selected in Vt line phase setting should be declared as dead to activate theLCM_TRIP.In midpoint mode, the SET_GROUP_CHANGE is activated and SWOTF output isactivated for a time of SWOTF time setting if the status of the phases selected is dead andif En set grp chg setting is TRUE.In tie point mode, the LCM_CLOSE is activated and also the SWOTF output is activatedfor a time of SWOTF time setting, if the status of the 3 phases of one source is live and thestatus of 3 phases of the other source is dead. And also the SET_GROUP_CHANGE isactivated, if source selected as line side is dead and if En set grp chg setting is TRUE.The S1_STATUS and S2_STATUS outputs, provides the status of the respective bus. Ifthe output is activated, it indicates the respective source is dead and vice versa.The binary input BLOCK can be used to block the function. The activation of the BLOCKinput deactivates all outputs and resets internal timers.Reset LogicThe loop control function is provided with reset logic for safety reasons. The reset logic isexplained for each of the loop control modes in the next few paragraphs.
