Toshiba GR-200 Series Instruction Manual page 118

Characteristics DT
N.A
DEF
N.A
N.A
N.A
DEP
N.A
N.A
N.A
Threshold value
2.5.3
The value of threshold current at which the OCN (I 2 ) element will pick-up is configured by
settings; the setting [OCN1] is provided for both the IDMT and the DT characteristic. Note
that the settings of the threshold levels are allowed to have distinct values in the respective
OCN elements. A rating current for the input is defined either 1A or 5A using System
parameter settings. (For more information about the rated current, see Chapter
description: Rated Frequency and Rated current
Reset Ratio
2.5.4
The ratio of the threshold current for pick-up to reset is applied using a setting; for example,
the ratio for the OCN1 element is set using the setting [OCN1-DPR]. The reset ratios for the
other OCN elements are also provided.
Miscellaneous functions
2.5.5
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 2.10.
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 2.20.
IEC-NI IEC-VI IEC-EI UK-LTI
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IDMT
IEEE-MI IEEE-VI IEEE-EI
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6F2T0200 (0.15)
US-CO2 US-CO8 Original
✓ ✓ ✓
✓
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Technical
GRE200 (1,2)