Toshiba GR200 Series Instruction Manual page 374

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Single shot scheme for an Arcing fault; fault removed by a backup

Figure 2.24-8 shows the single shot scheme for an Arcing fault, but tripping is not executed

due to the failure of the CB#1. Therefore, the operation of the ARC function is reset in the

setting time [TRESET] before the duration of dead timer [TTPAR1] expires. Consequently, the

ARC function determines that the local CB#1 cannot be tripped to clear the fault.

Fault current

Relay operation

ARC1 IN-PROG

ARC1-S1 IN-PROG

ARC1-S2 IN-PROG

ARC1-S3 IN-PROG

ARC1 CLOSE SUCCESS

ARC1 CLOSE FAIL

Figure 2.24-8 Single shot scheme [ARC-NUM]=S1 for an Arcing fault; remote CB† tripped

†Note: the fault is removed by the tripping of the CB at the remote end; hence, the fault

current will no longer flow.

Multi shot scheme for Permanent fault

Figure 2.24-9 illustrates the multi-shot scheme (S3); triple reclosing of the CB#1 by the ARC

function is required and executed correctly. However, the ARC function determines that the

fault is permanent as the fault persists after the third tripping (i.e. the shot counter logic

reaches its maximum value and the fault persists). Consequently, the ARC function moves to

the final trip (ARC1 FT) stage so that the ARC will not issue an 'ARC1 CLOSE COMMAND'

signal hereafter.

Fault cleared by tripping the backup CB at the remote end†

CB at the local end fails to open

Dead time [TTPAR1]

6F2S1915 (0.46)

GRZ200 (Soft 031 & 032)