Toshiba GR200 Series Instruction Manual page 293

Harmonic detection
(i)
The operation of each OCN element can be blocked using a scheme switch, if the ICD function
detects a second harmonic current caused by the magnetizing inrush current phenomenon
when a transformer is energized. For example, for the OCN1 element, the scheme switch
[OCN1-2fBlk] is provided, and Block should be set when the user wishes to block the OCN1
element when the second harmonic associated with magnetizing inrush is present. Non is set
for the scheme switch [OCN1-2fBlk] as the default setting. For more information about the ICD
function, see Chapter
Blocking OCN by VTF
(ii)
The operation of the OCN element can be blocked by the voltage transformer failure (VTF)
function via a scheme switch. For example, Block is set for the scheme switch [OCN1-VTFBlk]
to block the operation of the OCN1 element during a VTF condition. Non is set for the scheme
switch [OCN1-VTFBlk] as a default. For more information about the VTF, see Chapter
application: VT failure detection
Blocking OCN by CTF
(iii)
The operation of the OCN element can be blocked by the current transformer failure (CTF)
function via a scheme switch. For example, Block should be set for the scheme switch [OCN1-
CTFBlk] to block the operation of the OCN1 element during a CTF condition. Non is set for the
scheme switch [OCN1-CTFBlk] as a default. For more information about the CTF, see Chapter
Relay application: CT failure detection
OCN operation for autoreclose
(iv)
The OCN element activates the auto-reclose (ARC) function. However, if ARC is not required,
Block is set for the scheme switch [OCN1-ARCBlk]. Block is set for the scheme switch [OCN1-
ARCBlk] as a default.
Signal of OCN trip
(v)
When a user requires an alarm signal in place of the trip signal; for example, set Alarm for the
scheme switch [OCN1-UseFor]. Trip is set for the scheme switch [OCN1-UseFor] for the normal
trip operation.
Scheme logic
2.17.6
The scheme logic of both the non-directional and the directional OCN1 is illustrated in Figure
2.17-6; Figure 2.17-7 shows grouping commands for the trip circuit (TRC). The OCN1 signal is
generated when the pickup current exceeds a threshold, and then trip signals are injected into
the TRC. (For more information, see Chapter
Relay application: Inrush current detection function
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Relay application: Trip circuit function
6F2S1914 (0.49)
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Relay
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GRL200 (Soft 033 & 037)