Toshiba GRL150-100 Series Instruction Manual page 19

[RL-MODE]
M. RL
[OTD]
[DIFEN]
[DIF-FS]
[DIF-ICD]
(*1) Current values shown in parentheses are in the case of 1A rating. Other current values are in the
case of 5A rating.
(*2) In the actual setting, one terminal is set to "Master" and the other terminal to "Slave".
CT Ratio matching
If the CT ratios at the local and remote terminals are different, then CT ratio matching can be
applied as follows:
The differential element settings are respectively set to the setting values so that the primary fault
detecting current is the same value at all terminals. Figure 2.2.9.1 shows an example of CT ratio
matching. The settings for DIFI2 and DIFSV should also be set with relation to the primary
current in the same manner of the DIFI1 setting.
Terminal-A
CT ratio : 2000/1A
DIFI1=800A / CT ratio(2000/1A)
= 0.4A
Figure 2.2.9.1 Example of CT Ratio Matching
If the CT secondary ratings at the local and remote terminals are different, relay model suitable for
the CT secondary rating is used at each teminal and then CT ratio matching can be applied the
same as above. The differential element settings are respectively set to the setting values so that
the primary fault detecting current is the same value at all terminals. Figure 2.2.9.2 shows an
example of CT ratio matching. The settings for DIFI2 and DIFSV should also be set with relation
to the primary current in the same manner of the DIFI1 setting.
Terminal-A
GRL150
CT ratio : 2000/1A
DIFI1=800A / CT ratio(2000/1A)
= 0.4A
Figure 2.2.9.2 Example of CT Ratio Matching incase of Different CT secondary Rating
Auto / Manual
1.0 – 100.0% 0.1%
ON/OFF
ON/OFF
OFF / OC / OCD /
Both
NA / BLK
Primary sensitivity = 800A
GRL150
Primary sensitivity = 800A
1A rated model
⎯ 18 ⎯
Auto Signal receiving level adjusting mode
20.0% Signal receiving level (% of peak value)
OFF Open terminal detection
ON DIF enable
OFF Fail-safe function
NA DIF blocked by inrush current
Terminal-B
GRL150
CT ratio : 4000/1A
DIFI1=800A / CT ratio(4000/1A)
= 0.2A
Terminal-B
GRL150
5A rated model
CT ratio : 2000/5A
DIFI1=800A / CT ratio(2000/5A)
= 2.0A
6 F 2 S 0 8 2 8