Siemens SIPROTEC 7SD610, Руководство пользователя

Страница: 34 / 448

Functions
2.1 General
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
34
2.1.2 General Power System Data (Power System Data 1)
The device requires some plant and power system data in order to be able to adapt its functions accordingly,
depending on the actual 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 only be
changed from a PC running DIGSI and are discussed in this section.
2.1.2.1 Setting Notes
Current Transformer Polarity
In address
201 CT Starpoint
, the polarity of the current transformers must be entered, in other words, the
location of the CT star-point (Figure 2-1). 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 earth current input
I
E
.
Figure 2-1 Polarity of current transformers
Nominal Values of Transformers
In principle, the differential protection does not require any measured voltage. However, voltages can be con-
nected. These voltages allow to display and log voltages, and to calculate various components of power. If nec-
essary, they can also serve for determining the life line condition in case of automatic reclosure. During config-
uration of the device functions (Subsection 2.1.1), it has been determined whether the device is to work with or
without measured voltages.
In addresses
203 Unom PRIMARY
and
204 Unom SECONDARY
the device obtains information on the primary
and secondary rated voltage (phase-to-phase voltage) of the voltage transformers; in address
205 CT
PRIMARY
and
206 CT SECONDARY
the primary and secondary rated current transformers are set.
It is important to ensure that the secondary CT nominal current matches the rated current of the device, other-
wise the device will be blocked. The nominal current is set with jumpers on the measuring module (see 3.1.2).
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.