5.1.10.2 Explanation of Zone interconnection (Load transfer) function blockInputs• EXTSTART, when this binary input has logical value one the zoneinterconnection feature will be activated if it is enabled by the settingparameter Operation• SUMB1B2, this binary input is used for quite special feature which enables theuser to internally sum Bay 01 and Bay 02 currents while the zoneinterconnection is active• SUMB3B4, this binary input is used for quite special feature which enables theuser to internally sum Bay 03 and Bay 04 currents while the zoneinterconnection is active• SUMB5B6, this binary input is used for quite special feature which enables theuser to internally sum Bay 05 and Bay 06 currents while the zoneinterconnection is active. It shall be noted that this input is only available in 1-phase version of REB670.Outputs• ACTIVE, this binary output has logical value one while zone interconnectionfeature is active in the IED• ALARM, this binary output has logical value one, if the zone interconnectionfeature is active longer than the time set under setting parameter tAlarmSettings• Operation, this setting is used to switch On/Off zone interconnection feature.• tAlarm, this delay on start timer is used in order to give an alarm output whenzone interconnection feature is active for too long time. Timer can be set from0.00s to 6000.00s in step of 0.01s. Default value is 300.00s.5.1.10.3 Description of Zone interconnection operationZone interconnection can be activated by external signal or by internal logic insidethe IED, when a bay is connected to both zones, it means that zone interconnectioncan be activated by any particular bay. When the binary output signal ACTIVE isactivated, each CT will individually be include or exclude to the both zonesdepending on status of ZoneSwitching setting.1MRK 505 208-UEN B Section 5Differential protection145Technical reference manual
