Thytronic DMC3S - Page 67

67
DMC3S - Manual - 08 - 2021
For each of the thresholds I
ED
>, I
ED
>>
a
, I
ED
>>
b
, I
ED
>>> and I
ED
S
b
the angular trip semi-sector can be
regulated relative to the characteristic half-axis in the range 1…180°.
For all four thresholds (common configuration), (“Insens-Zone=ON”) activates and (“Ins-
ens-Zone=OFF”) deactivates a zone of insensitivity in the voltage current characteristic of protec-
tion 67N. When activated, the insensitivity zone remains defined between the set amperometric and
voltmetric thresholds and their values multiplied by M, which can be set in the range 1.5…10.0 for
all four thresholds together. This insensitivity zone can be used to prevent undesirable trip of the
protection due to permanent residual voltages and currents which violate the configured thresholds.
The parameters Insens-Zone (OFF, ON) and M can be set in the menu Set \ Protections \ Ground
directional overcurrent - 67N \ Common configurations.
Form
In modulus operating mode, if the protection is not switched to non-directional, the start (START) of
any threshold of protection 67N occurs when the following conditions A) and B) are both satisfied:
A) With “Insens-Zone=OFF”:
- Value of the residual current (I
E
) greater than the amperometric threshold (I
ED>
, I
ED>>
, I
ED>>>
, I
ED>>>>
)
AND
- Value of the residual voltage (U
E
or U
EC
) greater than the corresponding voltmetric threshold (U
ED>
,
U
ED>>
, U
ED>>>
, U
ED>>>>
).
With “Insens-Zone=ON”:
- Value of the residual current (I
E
) greater than the amperometric threshold (I
ED>
, I
ED>>
, I
ED>>>
, I
ED>>>>
)
AND
- Value of the residual voltage (U
E
or U
EC
) greater than the corresponding voltmetric threshold
(M∙U
ED>
, M∙U
ED>>
, M∙U
ED>>>
, M∙U
ED>>>>
)
OR
- Value of the residual current (I
E
) greater than the amperometric threshold (M∙I
ED>
, M∙I
ED>>
, M∙I
ED>>>
,
M∙I
ED>>>>
)
AND
- Value of the residual voltage (U
E
or U
EC
) greater than the corresponding voltmetric threshold (U
ED>
,
U
ED>>
, U
ED>>>
, U
ED>>>>
).
B) The residual current (I
E
) phasor is included in the angular sector with half-amplitude correspond-
ing to the regulation of the threshold in point A) with bisector the characteristic semi-axis of the
threshold in point A).
char-F67N-IeUe.ai
Voltage-current characteristic for the directional ground protection - 67N
with deactivation of the insensitivity zone
Voltage-current characteristic for the directional ground protection - 67N
with activation of the insensitivity zone
IE
(IED>, IED>>a, IED>>b, IED>>>, 67NSb)
(M∙IED>, M∙IED>>a, M∙IED>>b, M∙IED>>>, M∙67NSb)
TRIP
UE
UEC
IE
(IED>, IED>>a, IED>>b, IED>>>, 67NSb)
UED>,UED>>a,UED>>b,UED>>>,UEDSb
UED>,UED>>a,UED>>b,UED>>>,UEDSb
M∙UED>,M∙UED>>a,M∙UED>>b,M∙UED>>>,M∙UEDSb
TRIP
UE
UEC