Siemens SIPROTEC 7SD610 User Manual

2.1 General
33
7SD610 Manual
C53000-G1176-C145-4
Nominal Values of
Transformers
In principle, the differential protection does not require any measured voltage. Howev-
er, voltages can be connected. These voltages allow to display and log voltages, and
to calculate various components of power. If necessary, they can also serve for deter-
mining the life line condition in case of automatic reclosure. During configuration 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 in-
formation on the primary and secondary rated voltage (phase-to-phase voltage) of the
voltage 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 incorrectly calculate
primary amperes.
Correct entry of the primary data is a prerequisite for the correct computation of oper-
ational measured values with primary magnitude. If the settings of the device are per-
formed with primary values using DIGSI, these primary data are an indispensable re-
quirement for the correct function of the device.
Voltage Connection The device features four voltage measuring inputs, three of which are connected to
the set of voltage transformers. Various possibilities exist for the fourth voltage input
U
4
:
• Connection of the U
4
input to the open delta winding Ue–n of the voltage transform-
er set:
Address 210 is then set to: U4 transformer = Udelta transf..
When connected to the e-n winding of a set of voltage transformers, the voltage
transformation ratio of the voltage transformers is usually:
The factor Uph/Udelta (secondary voltage, address 211 Uph / Udelta) must be
set to 3/v3
= v3 ˜ 1.73. For other transformation ratios, i.e. the formation of the dis-
placement voltage via an interconnected transformer set, the factor must be cor-
rected accordingly. This factor is of importance for the monitoring of the measured
values and the scaling of the measurement and disturbance recording signals.
• If the input U
4
is not required, set:
Address 210 U4 transformer = Not connected.
Factor Uph / Udelta (address 211, see above) is also of importance in this case,
as it is used for scaling the measured data and fault recording data.
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Siemens SIPROTEC 7SD610 Specifications

General

Brand	Siemens
Model	SIPROTEC 7SD610
Category	Relays
Language	English