Toshiba GRZ100-211B, Instruction Manual

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6 F 2 S 0 8 3 4
the healthy line may be tripped erroneously. To prevent this, current reversal logic is provided.
(See Section 2.4.3.6 for current reversal.)
For the external communication channel, a single channel shared by different terminals or
multiplex channels, one channel for each direction can be used.
Scheme Logic
Figure 2.4.3.3 shows the scheme logic of the UOP. The logic level of transmit signal CS and
receive signal R1-CR and R2-CR is "1" for a trip block signal and "0" for a trip permission signal.
The UOP changes its transmit signal CS from a trip block signal to trip permission signal under
one of the following conditions. The logic level of CS changes from 1 to 0.
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The forward overreaching zone 2 or zone 3 selected by the scheme switch [ZONESEL]
operates and the current reversal logic (CRL) is not picked up. If the PLC signal
PSCM_TCHDEN is established, the delayed pick-up timer TCHD is provided.
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The circuit breaker is open and the trip permission signal (R1-CR=0, R2-CR=0) is
received from the other terminals.
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The forward overreaching zone 2 or zone 3 and reverse looking Z4 are not operating and
a trip permission signal is received from the other terminal.
The last two are implemented when an echo function (ECH) is selected. (Refer to Section 2.4.3.5
for echo function.)
Transmission of a trip permission signal continues for the TSBCT setting even after the local
terminal is tripped. This is to ensure that command tripping is executed at the remote terminal.
The UOP outputs single-phase tripping signal S-TRIP or three-phase tripping signal M-TRIP to
the local terminal when the trip permission signal (R1-CR=0, R2-CR=0) is received from the
remote terminals, the current reversal logic (CRL) is not picked up and one of the following
conditions is established.
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The forward overreaching element operates.
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The undervoltage element UVL (UVLS or UVLG) operates and the forward
overreaching and the reverse looking elements do not operate.
The latter is implemented when the weak infeed trip function is selected.
When the integral communication channel is used, the trip permission signals sent and received
contain three phase-segregated signals for earth faults and one signal for phase faults. When the
external communication channel is used, a single trip permission signal is common to all fault
types.
To select the faulted phase reliably, phase selection is performed using the phase selection element
UVC. Phase selection logic is described in Section 2.4.3.7.
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