RFL 9300 RFL Electronics Inc.
October 29, 2001 2 - 11 (973) 334-3100
The RFL 93B SV monitors all trip signals originating at both the local and remote terminals. If the RFL 9300 is
configured for three-pole trip operation and a trip signal (generated locally or remotely) is detected, a 150ms
timer is started. If trips are detected on all phases before this timer expires, a three-phase trip is said to exist,
and the reclose block output relay is energized for 50ms. If the RFL 9300 is configured for single-pole trip op-
eration and a trip signal is detected, a 3 second timer is started. If a trip signal is detected on another phase be-
fore this timer expires, and Selective Pole Relaying is not enabled, all three single-pole breakers will be tripped
and the reclose block output relay will be energized for 50ms. If Selective Pole Relaying is enabled, a trip signal
must be detected on all three phases before the 3 second timer expires before the reclose block output relay
will be energized.
The RFL 93B SV continuously monitors all system and communications alarm signals. If it detects an alarm, the
appropriate alarm relay will drop out, initiating an alarm. If it detects a communications alarm, the RFL 93B SV
will command the RFL 93B PC modules to enter the backup mode. The RFL 93B PC modules will disable per-
missive trip, but will only enter backup mode if the operator has enabled it. (See stub bus description in para-
graph 2.7.7) If the RFL 9300 is configured for single-pole trip operation and the relay is operating in backup
mode, any locally calculated trip signal that is detected will result in all three single-pole breakers being tripped
and a reclose block signal being issued. This is the case regardless of the status of the Selective Pole Relaying
option.
Only the RFL 93B CC can establish a communications alarm due to bad data or noise. The only communica-
tions alarm determined by the RFL 93B SV, is the channel delay alarm. This alarm is active when the channel
delay value received from the Communications Controller is greater than 31 ms.
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