Toshiba GR200 Series Instruction Manual page 215

is not received from the other terminals.
When On is set for scheme switch [Dis-ECHO], both the forward overreaching
✓
element and the reverse looking element are not operating and a trip block signal is
not received from the other terminals.
The selection of either the single-phase trip (1P) or the three-phase trip (3P) is carried
out using scheme switch [DisCAR-TPMD].
UOP issues single-phase tripping signal or three-phase trip signal locally when the
following conditions are established:
Trip block signal is not received from the opposite terminals.
✓
Current reversal is not observed
✓
One of the following conditions are observed:
✓
The forward overreaching element operates.
⚫
When On is set for scheme switch [Dis-WIKT], the undervoltage element UVL
⚫
(UVLS or UVLG) operates and the forward overreaching element (ZCSF/ZCGF)
and the reverse looking element (ZCSR/ZCGR) have not operated.
Blocking overreach protection (BOP)
2.12.4
BOP sends a trip block signal if the reverse overreach element operates and the forward
overreaching element dose not operate. Thus, at local terminal, CB tripping is performed when
the forward overreaching element has operated and a trip block signal has not been received
from the opposite terminal.
BOP does not send a trip block signal normally; and a trip block signal is sent only when
the reverse looking element operates. In BOP, a trip block signal is required to send in the
event of an external fault. Hence, failure operation or false operation can be removed when the
communication is performed by power line carrier,
BOP does not receive a trip block signal except by the occurrence of internal fault. If an
external fault occurs in forward, the forward overreaching element at a local terminal issues
a trip signal instantly. However, if an internal fault occurs, the reverse looking element at an
opposite terminal can operate and it transmits a trip block signal. At the local terminal, the
trip block signal will be received in the delay due to the propagation of communication channel.
Therefore, a short delay is required for CB tripping to check for the reception of a trip block
signal.
BOP can trip for any fault along the whole length of the protected line even if an open
terminal exists. A strong infeed terminal operates for all internal faults even if a weak infeed
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6F2S1914 (0.49)
GRL200 (Soft 033 & 037)