ABB REF615 - Auto Recloser DARREC

10.4 Auto recloser DARREC
10.4.1 Identification
Table 91: Function identification
IEC 61850 logical node name: DARREC
IEC 60617 identification: O-->I
ANSI/IEEE C37.2 device number: 79
10.4.2 Functionality
About 80 to 85 percent of faults in the MV overhead lines are transient and
automatically cleared with a momentary de-energization of the line. The rest of the
faults, 15 to 20 percent, can be cleared by longer interruptions. The de-energization
of the fault location for a selected time period is implemented through automatic
reclosing, during which most of the faults can be cleared.
In case of a permanent fault, the automatic reclosing is followed by final tripping. A
permanent fault must be located and cleared before the fault location can be re-
energized.
The auto-reclose function (AR) can be used with any circuit breaker suitable for auto-
reclosing. The function provides five programmable auto-reclose shots which can
perform one to five successive auto-reclosings of desired type and duration, for
instance one high-speed and one delayed auto-reclosing
When the reclosing is initiated with starting of the protection function, the auto-
reclose function can execute the final trip of the circuit breaker in a short operate time,
provided that the fault still persists when the last selected reclosing has been carried
out.
10.4.3 Application
Modern electric power systems can deliver energy to users very reliably. However,
different kind of faults can occur. Protection relays play an important role in detecting
failures or abnormalities in the system. They detect faults and give commands for
corresponding circuit breakers to isolate the defective element before excessive
damage or a possible power system collapse occurs. A fast isolation also limits the
disturbances caused for the healthy parts of the power system.
The faults can be transient, semi-transient or permanent. Permanent fault, for example
in power cables, means that there is a physical damage in the fault location that must
first be located and repaired before the network voltage can be restored.
In overhead lines, the insulating material between phase conductors is air. The
majority of the faults are flash-over arcing faults caused by lightning, for example.
Section 10 1MRS756378 D
Control functions
214 REF615
Application Manual