Siemens SIPROTEC 7UM62, Manual

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Inverse-Time Overcurrent Protection (ANSI 51V)
53
7UM62 Manual
C53000-G1176-C149-3
times of the setting value is present. The function will reset as soon as the value falls
below 95 % of the pick-up value.
The current is set at address
1402 Ip
. The maximum operating current is of primary
importance for the setting. A pickup caused by an overload must be excluded, as the
device operates in this mode as short-circuit protection with correspondingly short
relay times and not as overload protection.
The corresponding time multiplier for configuration of IEC characteristics (address
0114 O/C PROT. Ip
=
IEC Side n
) is accessible at address
1403 T Ip
. At
address
1405 IEC CURVE
, 3 IEC characteristics can be set.
The time multiplier for configuring ANSI characteristics (address
0114 O/C PROT.
Ip
=
ANSI Side n
) can be found at address
1404 TIME DIAL: TD
; parameter
1406
ANSI CURVE
offers a choice between 5 ANSI characteristics.
The time multipliers must be coordinated with the network grading plan.
The time multipliers can also be set to
∞
. If set to infinity, the stage will not trip after
pickup. However, the pickup is signalled. If the Ip stage is not required at all, set at the
address
0114 O/C PROT. Ip
=
Disabled
, or switch the function out by setting
1401
O/C Ip =
OFF
during configuration (see Section 2.2).
The address
1408
serves to predefine the
U<
pick-up value for the undervoltage trip
of the Ip pickup value for voltage-controlled inverse O/C time protection/AMZ
(parameter
1407 VOLT. INFLUENCE
=
Voltage controlled
). The parameter is
set to a value situated just below the lowest phase-to-phase voltage permissible
during operation, e.g. from 75 to 80 V. In this context, the same rules apply as for the
undervoltage seal-in of the definite O/C time protection (see also subsection 2.6.2).
If at address
1407 VOLT. INFLUENCE
=
Without
or
Voltage restraint
is set,
the parameter
1408
has no function.
2.8.2.1 Settings of the Inverse O/C Time Protection
The following list indicates the setting ranges and the default settings of a I
N
= 1 A
secondary nominal current. For a secondary nominal current of I
N
= 5 A, these values
must be multiplied by 5. Consider the current transformer ratios when setting the
device with primary values.
Addr. Setting Title Setting Options Default Setting Comments
1401 O/C Ip OFF
ON
Block relay for trip com-
mands OFF Inverse O/C Time Protection Ip
1402 Ip 0.10..4.00 A 1.00 A Ip Pickup
1403 T Ip 0.05..3.20 sec;
∞
0.50 sec T Ip Time Dial
1404 TIME DIAL: TD 0.50..15.00;
∞
5.00 TIME DIAL: TD
1405 IEC CURVE Normal Inverse
Very Inverse
Extremely Inverse Normal Inverse IEC Curve