ABB RER620 Technical Manual page 313

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RER620
Technical Manual
tripping RER620s, however, vary from the three phase units. With this option, you must
select whether you want to use the single phase tripping option or not in SDARREC
Settings. In three-phase tripping mode, the RER620 operates in the same manner as a unit
without the single-phase tripping option. Single-phase tripping is disabled. Three-phase
tripping is enabled.
In single-phase tripping mode, the phase that detects fault current (e.g., current above the
pickup threshold level) will initiate the recloser respective pole to trip open. In this mode,
for each protection group, the user may choose one of three modes of operation for
single-phase tripping: APAT (All Poles All the Time), OPUP (Only Picked Up Phases)
and OOAP (One Or All Phases).
Conditions on Single Phase Tripping
• When there is a single-phase fault and there is another phase that becomes involved,
the additional phase will immediately time out and trip on the curve associated with
the step that the other phase has tripped on last. However, all tripped phases will
reclose in tandem.
• When a single phase has locked out, the reset timer will count down from its set value
in the recloser settings. If another phase becomes involved before the reset time
expires, that phase will operate one shot to lockout. If, alternatively, the reset timer
has expired, the additional involved phase will go through the full sequence of
programmed operations.
• In single-phase tripping, the phase fault current must be greater than the phase
element pickup for the single-phase trip to occur. If the fault current is above the
neutral setting, but below the phase setting, a three-phase trip will occur.
• In the case where both the phase and ground element pick up (all phases must be
closed for neutral pickup), the trip time for the involved phases will be based on the
faster of the phase trip or the ground setting.
• After a single phase trip or lockout operation, all ground tripping is de-energized.
This prevents nuisance tripping of adjacent phases afterwards, due to load imbalance.
OPUP Mode - Only Picked Up Phases
If OPUP is selected, any respective phase that detects fault current by the RER620 is
actuated to open the respective pole of the recloser. The option for OPUP also allows each
pole on the recloser to open independently if the RER620 detects fault current on any of
the other two phases.
For example, suppose that a fault is detected on phase B. The RER620 will sense this
pickup and initiate a binary output signal from the RER620 to the recloser, the recloser will
trip open phase B and await timing from the RER620 for subsequent reclose or lockout.
Now suppose that during the pickup and subsequent trip of phase B, the RER620 senses
another fault on phase A. The RER620 will detect that fault and initiate a binary output
signal from the RER620 to the recloser for pole A, the recloser will trip open phase A and
then await timing from the RER620 for reclose or lockout. Comparable sequences may
occur and operation of the RER620 will continue to operate for phase C or any
combination of phase(s) caused by excessive load or fault current.
Section 5
Control functions
307