Toshiba GR200 Series Instruction Manual page 328

Condition fault occurrence
Fault observation by the relay
Issue of trip command
Incrimination of time counter
corresponding to the fault
duration.
T : Resetting time set by the user
1
T : Actual resetting time in the relay operation
2
T : Time gap between fault occurrence and relay start time
3
Figure 2.21-3 Faults occurrences and reset operation when IDMT being applied
Miscellaneous functions
2.21.4
OV operation blocked by the occurrence of VT failure
(i)
Blocking the OV function may be required when a failure in the voltage transformer occurs. In
this case, the user shall set Block for scheme switch [OV1-VTFBlk]. Non (as a default) is set
for scheme switch [OV1-VTFBlk] in order that the OV function is not blocked by the failure.
OV trip signal
(ii)
The OV function issues a trip command for the trip circuit (TRC†) when Trip is set for scheme
switch [OV1-UseFor] as the normal trip operation. However, when an alarm signal in place of
the trip command is required, the user can set Alarm for the scheme switch [OV1-UseFor].
†Note: For more information about the trip circuit, see Chapter
circuit
Execution of OV function
(iii)
Set On for scheme switch [OV1-EN]. Otherwise, set Off for the scheme switch [OV1-EN] if the
OV1 element is not required to operate.
Scheme logic
2.21.5
Figure 2.21-4 shows the OV1 logic. Signal connection points "OV1_BLOCK" are provided for
the block of the operation of the OV1 element. For testing, the OV1-PU element is provided; it
Intermittent fault
T
3
Trip level
T
1
T
2
Increment process in time
counter
.
- 305 -
Series faults
Tripping
T T
1 1
Value maintenance of time counter
6F2S1914 (0.49)
Relay operation reset
T
1
T
2
Reset of time counter
Relay application: Trip
GRL200 (Soft 033 & 037)