Siemens siprotec 7SD5 User Manual page 447

Voltages Connection examples for current and voltage transformer circuits are provided in Ap-
pendix A.3.
For normal connection the 4th voltage measuring input is not used. Correspondingly,
the following setting must be made in address 210 U4 transformer = Not
connected. Nevertheless, the factor in address 211Uph / Udelta must be set to
1.73 (this factor is used internally for the conversion of measured and fault recording
values).
For additional connection of an e-n-winding of a set of voltage transformers, address
210 must be set to U4 transformer = Udelta transf.. The factor address 211
Uph / Udelta depends on the transformation ratio of the e–n-winding. Instructions
- see Section 2.1.2.1 at „Voltage Transformer Connection".
In further connection examples also the e–n winding of a set of voltage transformers
is connected, in this case, however of a central set of transformers at a busbar. For
more information refer to the previous paragraph. Observe that 2-CT-connection is
permitted only for isolated or compensated networks.
Further figures show examples for the additional connection of a different voltage, in
this case the busbar voltage (e.g. for the voltage protection or synchronism check). For
voltage protection address 210 U4 transformer = Ux transformer must be set,
for the synchronism check U4 transformer = Usync transf.. The factor address
215 U-line / Usync is unequal to 1, only if the feeder side VT and busbar side VT
have a different transformation ratio. The factor in address 211 Uph / Udelta must
however be set to 1.73 (this factor is used internally for the conversion of measured
and fault recording values).
If there is a power transformer between the set of busbar and the feeder VT's, the
phase displacement of the voltages caused by the transformer must be considered for
the synchronism check (if used). In this case, also check the addresses 212 Usync
connect., 214 ϕ Usync-Uline and 215 U-line / Usync. You will find detailed
hints and an example in Section 2.1.2.1 under „Voltage Transformer Connection".
Binary Inputs and The connections to the system depend on the possible allocation of the binary inputs
Outputs and outputs, i.e. how they are assigned to the system. The presettings of the device
are listed in Tables A.4 in the Appendix. Check also that the labelings on the front cor-
respond to the allocated indication functions.
It is also very important that the feedback components (auxiliary contacts) of the circuit
breaker monitored are connected to the correct binary inputs which are assigned for
this purpose (if used).
Changing Setting If binary inputs are used to change setting groups, please observe the following:
Groups
• To enable the control of 4 possible setting groups 2 binary inputs have to be avail-
• To control two setting groups, one binary input set for „>Set Group Bit0" is suf-
• The status of the signals controlling the binary inputs to activate a particular setting
The following Table shows the relationship between binary inputs and the setting
groups A to D. Principal connection diagrams for the two binary inputs are illustrated
in the following Figure 3-1. The Figure illustrates an example in which both Set Group
7SD5 Manual
C53000-G1176-C169-1
able. One binary input must be set for „>Set Group Bit0", the other input for
„>Set Group Bit1".
ficient since the binary input „>Set Group Bit1", which is not assigned, is con-
sidered to be not controlled.
group must remain constant as long as that particular group is to remain active.
3.1 Mounting and Connections
447