ABB RER620 Technical Manual page 348

Section 5
Control functions
342
The condition for any source to be enabled in tie-point mode is to set the settings Vt line
enable and Vt load enable as TRUE and the respective source enable inputs should be
triggered with a positive pulse.
The source enable inputs S1_ENABLE and S2_ENABLE are pulse triggered inputs. This
is true if the present status of source is enabled. By applying a positive pulse to the
respective inputs the respective source will be disabled and vice versa.
Phase status determination
Phase status determination module determines the status of phases selected. The status of
phase can be live or dead or neither live nor dead based on the level of the respective phase
voltages.
The phase status logic compares the measured value of the respective phase voltage with
Live bus threshold and Dead bus threshold settings. If the measured voltage is greater than
Live bus threshold for a time of Live bus time then the respective phase is declared as live
bus. If the measured voltage is less than Dead bus threshold for a time of Dead bus time
then respective phase is declared as dead bus. If the measured voltage exceeds the Dead
bus threshold for a time less than Volt regain time then it is ignored by the function and
dead bus timer will be continuous during this time. If the voltage is restored for the Volt
regain time or longer, the dead bus timer is cleared and the status will change to either live
bus or neither live nor dead based on the voltage level. The phase is declared as neither
live nor dead if the phase voltage is above the Dead bus threshold and below the Live bus
threshold.
In sectionalizing mode, if Vt config line is "3" and the setting Sect3POpMode is selected
as "Any phase" then any of the 3 phases should be declared as dead to activate the
LCM_TRIP. If Sect3POpMode is selected as "Three phase" then all of the 3 phases should
be declared as dead to activate the LCM_TRIP. If Vt config line is "1" then the respective
phase selected in Vt line phase setting should be declared as dead to activate the
LCM_TRIP.
In midpoint mode, the SET_GROUP_CHANGE is activated and SWOTF output is
activated for a time of SWOTF time setting if the status of the phases selected is dead and
if En set grp chg setting is TRUE.
In tie point mode, the LCM_CLOSE is activated and also the SWOTF output is activated
for a time of SWOTF time setting, if the status of the 3 phases of one source is live and the
status of 3 phases of the other source is dead. And also the SET_GROUP_CHANGE is
activated, 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. If
the 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 BLOCK
input deactivates all outputs and resets internal timers.
Reset Logic
The loop control function is provided with reset logic for safety reasons. The reset logic is
explained for each of the loop control modes in the next few paragraphs.
1MAC309294-MB F
RER620
Technical Manual