• tTripPulse, this pulse timer is used in order to guaranty minimum trip pulseduration from the bay function block. Pulse time can be set from 0.000s to60.000s in step of 0.001s. Default value is 0.200s.• tZeroCurrent, this delay on start timer is used in order to unconditionally forcebay current to zero when ZEROCUR input into the function block has logicalvalue one. Time delay can be set from 0.000s to 60.000s in step of 0.001s.Default value is 0.200s.• tInvertCurrent, this delay on start timer is used in order to invert bay currentwhen INVCUR input into the function block has logical value one. Time delaycan be set from 0.000s to 60.000s in step of 0.001s. Default value is 0.200s.5.1.9.3 Bay operation principlesIn order to have properly balanced differential function for the station busbardisconnector switching arrangements, it is important to properly configure the zoneselection data for every connected current transformer. Due to this configurationparameter, the IED allows an effective application for stations where the zoneselection (that is, CT switching) is required. This is possible due to the softwarefacility to have full and easy control over all CT inputs connected to the terminal.The philosophy is to allow every CT input to be individually controlled by a settingparameter.The setting parameters for the differential protection function (DFB) are set via thelocal HMI or PCM600. See the technical reference manual for setting parametersand path in local HMI.Description of bay connectionThe setting parameter for bay connection called ZoneSel can be individually set forevery CT. ZoneSel can be set to only one of the following five alternatives:• FixedToZA, the CTx will be fixed to zone A.• FixedToZB, the CTx will be fixed to zone B.• FixedToZA&-ZB, the CTx is included to zone A and invert included to zone B.• CtrlIncludes, the CTx will be included to zone A/zone B when the input signalCTRLZA/CTRLZB is TRUE.• CtrlExcludes, the CTx will be included to zone A/zone B when the inputsignal CTRLZA/CTRLZB is FALSE (see figure 63).When the last two options are used the CT input can be dynamically included orexcluded from the differential zone by simply controlling the dedicated inputs ofthe Bay function block.Section 5 1MRK 505 208-UEN BDifferential protection138Technical reference manual
