Toshiba GR200 Series Instruction Manual page 106

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Command distance protection

‡Note: For more information about the ARC function, see chapter

Autoreclosing function

§Note: For the transient fault, the power transmission could be recovered transiently by

the operation of the ARC function, whereas the zone1X cannot operate effectively

for the permanent fault (i.e., more of the network will be lost than necessary). We

recommend one to use the DISCAR function when the DISCAR function is

Tips to set the distance zones for multi-terminal lines

Setting for reverse zones (Zone4 served as a backup relay)

Suppose multi-terminal lines (AJ, FJ, and JK) are configured behind the busbar A, as shown

in Figure 2.1-57. The line AB may be required to protect by the remote-backup relay

together with the main (primary) relay

than the zone3

. That is, it is difficult for the zone3

backup relay for the line AB once a fault occurs on the line AB, because a fault current is fed

from several busbars. On the other hand, the fault current feeding will not influence the

operation of the zone4

Figure 2.1-57 Reverse zone protection for multi-terminal lines

Setting for the primary zone (Zone1 and a junction)

Suppose that a line AC is connected at line AF at junction J, as shown in Figure 2.1-58. The

may underreach due to a feeding current behind busbar A, whereas, the zone1

allowed to overreach for any fault on the busbar B. Hence, the zone1

can operate correctly for any faults within the protected zone even if a power source does not

exist behind busbar B. Accordingly, as for the fault on the line AB, the user should have

. However, the zone4

(or the zone3

6F2S1915 (0.46)

Relay application:

may operate more effectively

) to service a remote

must be set so that it

GRZ200 (Soft 031 & 032)