ABB Relion 620 Series, Руководство по применению

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Section 3
RER620 application
RER620 57
Application Manual
loads. It provides a control capability function of the recloser to trip and/or lockout
whenever there is a fault on one-phase, two-phases or three-phases. This feature allows an
electric utility to prevent unnecessary three-phase interruptions and outages of their
distribution network where a majority of outages can be attributed to single-phase transient
type faults thereby improving the overall power system reliability and quantity of power
delivered to customers on the distribution feeder.
3.4.1 Overview of the features in single-phase tripping
As an example of single-phase operation of an RER620 with a recloser, imagine that the
recloser is protecting a rural three-phase line. Suppose that a fault occurs on A-phase,
where the fault is permanent and there is no fuse between the recloser and the fault. A
conventional three-phase recloser will trip for two instantaneous operations followed by
two time-delayed operations. The single-phase fault on A-phase will cause all customers
downstream to experience three interruptions of power and an outage until the fault is
repaired, cleared and the recloser restored to normal operation. The RER620 with
single-phase tripping can operate the recloser for the same single-phase fault on A-phase
as a single-pole trip, reclose and lockout. This provides a significant advantage to 67% of
the customers downstream of the fault since their power is not interrupted. The operation
of single-phase operation will trip for two instantaneous operations, two time-delayed
operation and lockout on the A-phase pole. Since the fault is a permanent
single-phase-to-ground fault, (e.g. A-N), the load connected to A-phase will experience an
outage but the other two phases (e.g. B-phase and C-phase) will not experience any
interruption of power and will stay energized.
The single phase tripping option is designed to be extremely flexible in order to meet the
most demanding requirements. Listed below are brief descriptions of the features for
single-phase and three-phase tripping operation:
RER620s supplied with the single phase tripping option consist of the same hardware
(front panel and modules) as the standard three phase units. Settings for single phase
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).
3.4.1.1 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.