Or 2 Phase Vt Fail; Phase Vt Fail - Siemens 7SR21 Manual

3.2.1

1 or 2 Phase VT fail

Apply 3P balanced nominal current and voltage. Reduce 1 phase voltage until VTS operates, record voltage
reduction level.
60VTS V Setting
Increase the voltage until VTS resets. Increase current on 1 phase by 110% of 3x the 60VTS I setting. Reduce
voltage as above and check for no operation. Return voltage to nominal. Increase current on 1 phase by 90% of
3x the 60VTS I setting. Reduce voltage as above and check for VTS operation
60VTS I Setting
3.2.2

3 Phase VT fail

Apply 3P balanced nominal voltage and 3P balanced current at a level between the 60VTS Ipps Load setting and
the 60VTS Ipps Fault setting. Reduce the balanced Voltage on all 3 phases until the VTS operates at the 60VTS
Vpps setting. Return the voltage to nominal and ensure that VTS resets.
Reduce the 3P balanced current to a level below the 60VTS Ipps Load setting. Reduce the 3P balanced voltage
to a level below the operate level above. Gradually increase the 3P balanced current until the VTS operates.
Check that the thermal rating of the relay current inputs is not exceeded during the following test. Increase the 3P
balanced current to a level above the 60VTS Ipps Fault setting. Reduce the 3P balanced voltage to a level below
the operate level above. Gradually reduce the 3P balanced current until the VTS operates.
60VTS Vpps
60VTS Ipps Load
60VTS Ipps Fault
If the VTS can be started from a status input fed from an external source, this functionality should be tested.
Ext_Trig 60VTS Operation □
3.2.2.1 Element Blocking
The VT Supervision can be blocked by Binary Input Inhibit. This functionality should be checked.
Element
60VTS
©2010 Siemens Protection Devices Limited
7SR21 & 7SR22 Argus Commissioning and Maintenance
Setting x 3
Setting x 3 110% of Setting x 3
Setting
Not Applicable
Measured Voltage Reduction
No VTS □
□
BI Inhibits
Chapter 6 Page 60 of 69
90% of Setting x 3
VTS operation □
Measured