General Power System Data (Power System Data 1); Setting Notes - Siemens siprotec 7SD5 User Manual

2.1.2

General Power System Data (Power System Data 1)

The device requires certain network and power system data so that it can be adapted
to its intended functions in accordance with application. This comprises, e.g., nominal
system data, nominal data of transformers, polarity ratios and their physical connec-
tions, in certain cases circuit breaker properties, and similar. Furthermore, there are
a number of settings associated with all functions rather than a specific protection,
control or monitoring function. These data can only be changed from a PC running
DIGSI
2.1.2.1

Setting Notes

In address 201 CT Starpoint, the polarity of the wye-connected current transform-
Polarity of Current
Transformers ers is specified (the following figure also goes for only two current transformers). This
setting determines the measuring direction of the device (forwards = line direction). A
change in this setting also results in a polarity reversal of the earth current inputs I
I
Figure 2-2
If voltage transformers are connected, the device obtains in addresses 203 Unom
Nominal Values of
PRIMARY and 204 Unom SECONDARY information on the primary and secondary
the Transformers
nominal voltage (phase-to-phase voltage), and in addresses 205 CT PRIMARY and
206 CT SECONDARY information on the primary and secondary nominal currents of
the current transformers (phases).
Address 206 CT SECONDARY must correspond to the nominal current of the device,
otherwise the processor system cannot be started.
The correct primary data are required for the calculation of the proper primary infor-
mation of the operational measured values. If the settings of the device are performed
with primary values using DIGSI
ment for the fault-free operation of the device.
In principle, the differential protection is designed such that it can operate without mea-
sured voltages if it is configured as the main protection function without distance pro-
tection function. However, voltages can be connected. These voltages allow to display
and log voltages, to calculate various components of power and to locate faults. If nec-
7SD5 Manual
C53000-G1176-C169-1
®
and are discussed in this section.
.
EE
Polarity of current transformers
®
, these primary data are an indispensable require-
2.1 General
or
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