Toshiba GR200 Series - 2.34.2 Terminology; (i) Relay operation period; (ii) Temporary;transient;Arc fault; (iii) Arcing time of CB

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
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2.34.2 Terminology
The terminology and signals outlined below are applicable for single CB#1 system. Signals
applicable for CB#2 in a two (2) CB system are similar and are not included for clarity.
(i) Relay operation period
The time interval commencing from the instant of the relay picking-up for the fault current to
the instant of the relay dropping-off following the cessation of the fault current.
(ii) Temporary/transient/Arc fault
A transient/temporary fault, the main cause of which is often due to lightning, (an over voltage
induced in a line due to the static electricity caused by the lightning may cause a flash over
across the insulator string), temporary contact with foreign objects, conductor clashing as a
consequence of strong wind.
(iii) Arcing time of CB
When the CB#1 contacts separate during tripping, an arc is produced between the CB#1
contacts; the arc is extinguished by the interrupting medium in the CB#1. The duration of
arcing is called the ‘Arcing time’, which is the time between the instant of separation of the
circuit breaker contacts and the instant of the extinction of the fault arc.
(iv) Permanent fault (Signal ‘ARC1 FT’)
Fallen conductors, tree growth, tree branches that have fallen across lines, as well as other
causes, may all produce permanent faults. As the operation of the ARC function is unable to
restore power transmission for permanent faults, the ARC function abandons the reclosing of
the CB#1, defined as the ‘Final trip (ARC1 FT)’ stage. If the ARC function gets into the ‘ARC1
FT’ stage, closing the CB#1 is only possible by the manual operation.
(v) Signal shot scheme (Signal ‘ARC1 SHOT1’)
The ARC function issues a first auto-reclosing signal ‘ARC1 SHOT1’ when a ‘GEN.TRIP’ signal
is issued in the trip circuit (TRC†) by the first relay operation. When the user programs the
ARC function not to provide subsequent reclosures, this operating sequence provides only one
reclosing operation; then, lockout will occur on subsequent tripping, i.e. the ‘Final trip (ARC1
FT)’ stage.
†Note: For more information, see chapter Relay application: Trip circuit .
(vi) Multi shot scheme (Signals ‘ARC1 SHOT2–5’)
Signals ‘ARC1 SHOT2’ to ‘ARC1 SHOT5’ may be issued after the ‘ARC1 SHOT1’ signal when
a persistent fault occurs.