Toshiba GR200 Series Instruction Manual page 508

Current transformer failure (CT fail)
9.2.24
Detecting the open-circuit in CT is achieved by the operation of the CT failure detection
function†. Thus, the failure signal in the CTF is transferred to the automatic supervision
function and it is grouped into the error level together with other error signals.
†Note: For more information about the CT failure function, see Chapter
application: Current differential protection: CT circuit failure detection
Error level
(i)
The default error level is set at level 3 (Minor error), but the user can program the level using
setting [CHK_CTF:LVl]; then, set On for the setting [CHK_CTF:Sw]. The manufacture sets ten
(10) seconds detect the failure; it is reset instantly when the failure is cleared.
Error message
(ii)
When detecting an error, an error message can be shown on the LCD screen and an LED is lit.
Table 9.2-50 Error messages provided by the supervisor in CHK_CTF_CBP
Message and level
CT fail
Error level
Table 9.2-51 Detailed information in Hexadecimal in CHK_CTF_CBP
Display
area
10000000:
01000000:
Top
00100000:
00010000:
row
00001000:
00000100:
Middle
(No information displayed)
row
Bottom
(No information displayed)
row
Detection of the open circuit in the CT
Minor error (Level 3)
Meaning of the detailed information
Left column
ZoneA
ZoneB
ZoneC
ZoneD
ZoneE
ZoneF
- 494 -
Meaning of the information
Right column
00000010:
00000001:
(No information displayed)
(No information displayed)
6F2S1931 (0.20)
Relay
.
Checkzone
ORed state in all zones
Centralized GRB200
(Soft: 030, 031, 032, 033, 034)