ABB RER620 Technical Manual page 353

1MAC309294-MB F
RER620
Technical Manual
Once the SWOTF timer expires, the unit goes into normal reclosing mode to allow
isolation of any subsequent temporary faults.
Note that the Tie-point loop control mode also enables SWOTF output 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.
SET_GROUP_CHANGE settings refer to alternate current thresholds used by the
RER620 in recognizing overcurrent conditions. This is important in the Midpoint and
TiePoint reclosers because their loads and protective settings may vary depending on
which source is supplying the power. The user can optionally program both the Midpoint
and TiePoint reclosers to switch to another group settings when initiating loop control
sequences.
Because of the additional reclosers in a five-recloser system, there are three potential fault
locations on each side of the TiePoint:
• Between source and Sectionalizing recloser
• Between Sectionalizing and Midpoint reclosers
• Between Midpoint and TiePoint reclosers
S1
S2
Figure 185: 5-Recloser Loop Control
5-Recloser Fault 1 Scenario
In a 5-recloser loop control scheme, Figure 185, if there is a permanent fault between the
S1 circuit breaker and the sectionalizing recloser B at F1, the S1 circuit breaker will
recognize the fault and go through its reclosing shots to lockout (for illustration purposes
we will assume 3 operations to lockout for all devices). Recloser B will recognize a loss
Section 5
Control functions
347