Siemens SIPROTEC 4, Руководство пользователя

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running. After the dropout delay time has elapsed, the pickup is reported OFF and the trip delay time is reset
unless the threshold has been exceeded again. If the threshold is exceeded again during the dropout delay
time, the time is canceled. The trip command delay time continues running. Should the threshold value be
exceeded after its expiry, the trip command is issued immediately. If the threshold value is not exceeded at
this time, there will be no reaction. If the threshold value is exceeded again after expiry of the trip-command
delay time, while the dropout delay time is still running, tripping occurs immediately.
The configured dropout times do not influence the tripping times of the inverse time elements as these
depend dynamically on the measured current value. For purposes of dropout coordination, disc emulation is
used with electro-mechanical relays.
Setting Notes
General
The function type has been specified during configuration of the protection functions (see Section
2.1.1.2 Setting Notes , address 140,
46
). If only the definite time elements are desired, the address
46
should
be set to
Definite Time
. Selecting
46
=
TOC IEC
or
TOC ANSI
in address 140 will additionally make all
parameters available that are relevant for the inverse time characteristics. If this function is not required, then
Disabled
is set.
The function can be turned
ON
or
OFF
in address 4001
FCT 46
.
The default pickup settings and delay settings are generally sufficient for most applications. If data is available
from the manufacturer regarding the allowable long-term load imbalance and the allowable load imbalance
per unit of time, this data should be used preferentially. It is important to note that the manufacturer's data
relate to the primary values of the machine, for example, the maximum permissible permanent inverse
current is referred to the nominal machine current. For the setting values at the protection device, this infor-
mation is converted to the secondary inverse current. The following applies
[einstellwert-i2-260602-kn, 1, en_US]
with
Ι
2 perm prim
permissible thermal inverse current of the motor
Ι
Nom Motor
Nominal Motor Current
Ι
CT sec
Secondary Nominal Current of the Current Transformer
Ι
CT prim
Primary nominal current of the current transformer
Definite Time Elements
The unbalanced load protection function comprises two elements. Therefore, the upper element (address
4004
46-2 PICKUP
) can be set to a short time delay 4005
46-2 DELAY
) and the lower element (address
4002 46- 1 PICKUP) can be set to a somewhat longer time delay (address 4003
46-1 DELAY
). This allows the
lower element to act, e.g. as an alarm, while the upper element will cut the inverse time characteristic as soon
as high inverse currents are present. If
46-2 PICKUP
is set to about 60%, tripping is always performed with
the thermal characteristic. On the other hand, with more than 60% of unbalanced load, a two-phase fault can
be assumed. The delay time
46-2 DELAY
must be coordinated with the system grading of phase-to-phase
faults. If power supply with current I is provided via just two phases, the following applies to the inverse
current:
[formel-i2-058-260602-kn, 1, en_US]
Examples:
Motor with the following data:
2.7.3
Functions
2.7 Negative Sequence Protection 46
140 SIPROTEC 4, 7SJ62/64, Manual
C53000-G1140-C207-8, Edition 08.2016