Toshiba GRL150-100 Series Instruction Manual page 18

Note: GRL150 operation depends on the transmission performance of the pilot wire cable and the
noise environment, and where these are poor the circuit lengths quoted above may not be
achievable.
The GRL150-100 series is applied to pilot wire communication only. The GRL150-400 series can
be applied to pilot wire communication or fibre optic communication by scheme switch
[COM.I/F]. In the case of pilot wire communication, the [COM.I/F] is set to "PW". For fibre optic
communication, it is set to "OPT".
In pilot wire communication, a receiving signal adjusting function is provided, since the receiving
level is influenced by pilot-wire cable size, distance and installation environment. The receiving
signal can be adjusted automatically (Auto) or manually (Manual) by the scheme switch
[RL-MODE]. When "Auto" is selected, the optimum signal receiving level, which has the least CF
(Communication Failure), is automatically set according to the receiving level (peak value).
"Auto" is generally selected in normal operation. However, if a severe noise environment prevents
correct operation of GRL150, then "Manual" can be selected and the receiving level is chosen
manually. (Refer to Section 4.2.3.4, 4.2.6.5 and 6.6.2.)
If the transmitting signal interferes with other communication signals in a multi-core pilot wire
cable, the optional G1RE1 resistor box is available for reducing the transmission level. (Refer to
Appendix N.)
2.2.8 Telecommunication Channel Monitoring
If a failure occurs or noise causes a disturbance in the telecommunication channel, they may
interrupt the data transmission or generate erroneous data, thus causing the relay to operate
incorrectly.
The GRL150 detects data failures by performing a cyclic redundancy check on the data. The
checks are carried out for every sample. (See Section 3.3.5.)
If the failure lasts for ten seconds, a communication failure alarm is issued.
Current differential protection is blocked instantaneously upon detection of a communication
failure. The output blocking ceases instantly when the failure recovers.
2.2.9 Setting
The following shows the setting elements necessary for the current differential protection and their
setting ranges. The settings can be made on the LCD screen or PC screen.
Element
DIF
DIFI1
DIFI2
OC5
DIFSV
TIDSV
[SP.SYN]
[COM.I/F]
Range Step
0.50 − 10.00A
0.01A
(0.10 − 2.00A
0.01A
1.0 − 120.0A
0.1A
(0.2 − 24.0A
0.1A
0.1 – 250.0A 0.1A
(0.02 – 50.00A 0.01 A
50 – 100% 1%
0 – 60s 1s
Master/Slave
PW / OPT
⎯ 17 ⎯
Default Remarks
Phase current
5.00A Small current region
1.00A)(*1)
15.0A Large current region
3.0A)
2.5A OC5 threshold setting for fail-safe
0.5A)
50% Differential current Id monitoring
10s Timer for Id monitoring
Master(*2) Sampling synchronization
OPT Only for model 400 series
6 F 2 S 0 8 2 8