• Grounded - Select this option by using the parameter setting SCBGndType, if the capacitor bank is
grounded.
• Ungrounded - Select this option by using the parameter setting SCBGndType, if the capacitor bank
is ungrounded.
Ensure that the three-phase bus voltage and the tap voltage are connected to the
separate SMAI blocks and their outputs are connected to the V3P and U3PTAP inputs of
the SCPDPTOV function.
In case of ungrounded capacitor bank configuration, if the neutral voltage is available,
ensure that it is connected to the SMAI block and the SMAI output is connected to the
U3NEUT input of the SCPDPTOV function.
Verifying the function in Grounded mode
GUID-78835D73-AC7D-4D58-998F-82B5AFC2E8CD v1
Perform the following procedure to test the function in Grounded mode.
1. Set the following parameters:
• Operation = Enable
• tDefWrn = 5 s; tDefAlm = 5 s; tDefTrip =5 s
• SCBGndType = Grounded
• Udif> =10% UB
• UdifAlm> =8% UB
• UdifWrn> =5% UB
• UMin> =50% UB
• VoltRatioL1 =0.5
2. Activate RESETCOMP input to ensure that the stored values are reset.
3. The expected output is monitored in the following path from the local HMI client: Main menu /Test/
Function status /Unbalance protection/CapBankPhaseVoltageDiff(87V, Ud>)/SCPDPTOV(87V,
Ud>):x/Outputs , where x = instance number.
4. Check the respective operation of warning, alarm, and trip.
Step no.
Changes after step 2 Expected output
4-a* Inject constant bus voltages of U
L1
= 63.51 V
at 0°, U
L2
= 63.51 V at 240°, and U
L3
= 63.51
V at 120° in secondary at rated frequency
• UL1, UL2, and UL3 should
show 230.94 kV
• UNSCB should show 0 kV
4-b Inject constant tap voltage of U
TapL1
= 31.75 V
in secondary at rated frequency
UTAPL1 should show 115.47 kV
RESETCOMP test
4-c Activate binary input RESETCOMP for 1 s USEDURATL1 should show 0.5
(VoltRatioL1)
TRIGCOMP Test
Repeat Sub-step 4–a
4-d Inject U
TapL1
= 24.25 V in secondary at rated
frequency
• DIFURATL1 should
become HIGH
• URATIOL1 and
USEDURATL1 should
show 0.382 and 0.5
respectively
Table continues on next page
1MRK 504 165-UUS Rev. J Section 11
Testing functionality by secondary injection
Transformer protection RET670 221
Commissioning manual
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