Siemens SIPROTEC 7SJ62 Manual page 47

Distance Unit (Power System)
Address 215 Distance Unit allows you to specify the distance unit (km or Miles) for the fault locator. In the
absence of a fault locator or if this function has been removed, this parameter is of no importance. Changing
the distance unit does not imply an automatic conversion of the setting values that are dependant on the dis-
tance unit. These have to be re-entered at the respective addresses.
ATEX100 (Power System)
Parameter 235 ATEX100 enables meeting the requirements for protecting explosion-protected motors for
thermal replicas. Set this parameter to YES to save all thermal replicas of the 7SJ62/64 devices in the event of
a power supply failure. After the supply voltage is restored, the thermal replicas will resume operation using the
stored values. Set the parameter to NO, to reset the calculated overtemperature values of all thermal replicas
to zero if the power supply fails.
Nominal Values of Current Transformers (CTs)
At addresses 204 CT PRIMARY and 205 CT SECONDARY information is entered regarding the primary and
secondary ampere ratings of the current transformers. It is important to ensure that the rated secondary current
of the current transformer matches the rated current of the device, otherwise the device will calculate incorrect
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 transformer. In case of a normal connection (starpoint
current connected to I
value.
If the device features a sensitive ground current input, parameter 218 Ignd-CT SEC is set to 1 A by default.
In this case, the setting cannot be changed.
If address 251 has been set so that ground currents are measured by two inputs (setting options A,G2,C,G;
G->B or A,G2,C,G; G2->B), you have to set the primary rated current of the second ground transformer con-
at address 238. secondary ampere rating must conform with the phase current transformer.
nected to I
N2
To calculated the phase current I
is used to calculate I
phase current transformer (address 204).
Nominal Values of Voltage Transformers (VTs)
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.
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
transformer), 217 Ignd-CT PRIM and 204 CT PRIMARY must be set to the same
N
correctly, the primary rated current of the ground current transformer, which
B
(address 217 or address 238), must be smaller than the primary rated current of the
B
Functions
2.1 General
47