Functions
2.1 General
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
37
2.1.3 General Power System Data (Power System Data 1)
The device requires certain data regarding the network and substation so that it can adapt its functions to this
data depending on the application. The data required include for instance rated data of the substation and the
measuring transformers, polarity and connection of the measured quantities, if necessary features of the circuit
breakers, and others. Furthermore, there are several function parameters associated with several functions
rather than one specific protection, control or monitoring function. The Power System Data 1 can generally only
be changed from a PC running DIGSI and are discussed in this section.
2.1.3.1 Setting Notes
Polarity of Current Transformers
In address 201 CT Starpoint the polarity of the current transformers must be entered, in other words, the
location of the CT starpoint (Figure 2-2). The setting defines the measuring direction of the device (current in
line direction is defined as positive at both line ends). The reversal of this parameter also reverses the polarity
of the ground current input I
N
.
Figure 2-2 Polarity of current transformers
Nominal Values of Transformers
In addresses 203 Vnom PRIMARY and 204 Vnom SECONDARY the device obtains information on the primary
and secondary rated voltage (phase-to-phase voltage) of the voltage transformers.
The voltage connection is required for all functions that work on the basis of power or voltage values, e.g.
ground fault differential protection in resonant-grounded/isolated systems, directional overcurrent protection,
voltage protection, frequency protection, and to display and record the voltages.
Please make sure that the rated secondary transformer current matches the rated current of the device.
Correct entry of the primary data is a prerequisite for the correct computation of operational measured values
with primary magnitude. If the settings of the device are performed with primary values using DIGSI, these
primary data are an indispensable requirement for the correct function of the device.
To Next Page
Loading...
Need help?
General
