Siemens siprotec SJ62 User Manual page 48

Distance Unit
ATEX100
Two-phase Time
Overcurrent Pro-
tection (Power
System Data)
Ground Fault Pro-
tection
Voltage Protection
(Switchover of
Characteristic
Values)
Nominal Values of
Current Transform-
ers (CTs)
Nominal Values of
Voltage Transform-
ers (VTs)
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
Address 215 Distance Unit corresponds to the unit of length (km or Miles) appli-
cable to fault locating. If a fault locator is not included with the device, or if the fault
locating function is disabled, this setting has no effect on operation of the device.
Changing the length unit will not result in an automatic conversion between the sys-
tems. Such conversions must be entered at the appropriate addresses.
Address 235 ATEX100 allows that the requirements for the protection of explosion-
protected motors with regard to thermal profiles is fulfilled. Set this parameter to YES
to save all thermal replicas of devices 7SJ62/63/64 in the event of a power supply fail-
ure. After the supply voltage is restored the thermal profiles will resume operation
using the stored values. Set the parameter to NO to reset the calculated overtempera-
tures of all thermal profiles to zero if the power supply fails.
Two-phase time overcurrent protection is used in isolated or resonant-grounded
systems where three-phase devices are desired to coact with existing two-phase pro-
tection equipment. Parameter 250 50/51 2-ph prot can be set to specify whether
the overcurrent protection operates in two or three phases. If set to ON, threshold com-
parison uses always the value 0A instead of the measured value for I
B can not initiate a pick-up. All other functions operate however in three phases.
With address 613 Gnd O/Cprot. w. define whether ground fault protection either
is to operate using measured values (Ignd (measured)) or the quantities calculated
from the three phase currents (3I0 (calcul.)). In the first case, the measured
quantity at the fourth current input is evaluated. In the latter case, the summation
current is calculated from the three phase current inputs. If the device features a sen-
sitive ground current input (measuring range starts at 1 mA), the ground fault protec-
tion always uses the calculated quantity 3I0. In this case, parameter 613 Gnd
O/Cprot. w. is not available.
With three-phase connection, the fundamental harmonic component of the largest of
the three phase-to-phase voltages (Vphph) is supplied to the overvoltage protection
elements, or the negative sequence voltage (V2). With three-phase connection, und-
ervoltage protection relies either on the positive sequence voltage V1 or the smallest
of the phase-to-phase voltages Vphph. These specifications can be configured via pa-
rameter 614 OP. QUANTITY 59 and 615 OP. QUANTITY 27. If voltage transform-
ers are connected single-phase, there is a direct comparison of measured values and
thresholds, and the setting of characteristic values switchover is ignored.
At addresses 204 CT PRIMARY and 205 CT SECONDARY, information is entered re-
garding the primary and secondary ampere ratings of the current transformers. It is im-
portant to ensure that the rated secondary current of the current transformers matches
the rated current of the device, otherwise the device will incorrectly calculate primary
data. At addresses 217 Ignd-CT PRIM and 218 Ignd-CT SEC, information is
entered regarding the primary and secondary ampere rating of the current transform-
ers. In case of normal connection (starpoint current connected to I
Ignd-CT PRIM and 204 CT PRIMARY must be set to the same value.
If the device features a sensitive ground current input, address 218 Ignd-CT SEC is
set to 1 A. In this case setting cannot be changed.
At addresses 202 Vnom PRIMARY and 203 Vnom SECONDARY, information is entered
regarding the primary nominal voltage and secondary nominal voltage (phase-to-
phase) of the connected voltage transformers.
2.1 General
, so that phase
B
–transformer) 217
N
46