Siemens Argus 7SR22 - Busbar VT Fail (60 VTF-Bus) - 7 SR22; Figure 5.2-1 Logic Diagram: VT Supervision Function (60 VTS)

7SR210 & 7SR220 Description of Operation
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Enabled
Disabled
&
60VTS Element
&
&
>
1
60VTS Ext_Trig
&
S
R
Q
>1
60VTS Operated
&
60VTS Inhibit
1 or 2 Phase Fail
V
V Setting
>
I
I Setting
<
V1
Vpps Setting
<
I1
Ipps
<
3 Phase Fail
I1
Ipps Load
>
60VTS Ext_Reset
60VTS Delay
NPS/ZPS
60VTS
Component
VL1
VL2
VL3
Phase
Seq.
Filter
IL1
IL2
IL3
Phase
Seq.
Filter
V2
V0
I2
I0
V1
I1
60VTS Inhibit
60VTS Pick-Up
60VTS Operated
Figure 5.2-1 Logic Diagram: VT Supervision Function (60VTS)
5.3 Busbar VT Fail (60VTF-Bus) – 7SR22
When the optional synchronising function is fitted, the synchronising voltage transformer is utilised to provide an
additional monitoring function to check the validity of the measured line and busbar voltages. When the circuit
breaker is closed, both voltages should be either Live or Dead. If the Bus voltage indicates that the VT is Dead
but the corresponding Line voltage is Live, this raises the Bus VT Fail output. A time delay setting is provided to
avoid spurious operations during transient switching conditions. Additionally, this output can be enabled by a
setting, 79 LO Bus VT Fail, to apply a Lockout signal to the autoreclose function so that a sequence will not be
attempted after a trip occurs if it is known that the voltage measurement is not reliable. A similar setting is
available, 79 LO Line VT Fail, which when Enabled will provide a Lockout for a Line VT failure detected by the
60VTS function.