• VoltageInput = 3×ZeroSeq
• I > = 125% IBase
• VDepFact1 = (1-117)/I> = 0.064
2. Values of the logical signals and service values for SCCFPVOC (51 V) are available on the local
HMI under: Main menu/Tests/Function status/Unbalance protection/
CapBankCascadingFail(51V,2(I>/U<))/SCCFPVOC (51V, 2(I>/U<)):x, where x = instance number.
The Base values, CT and VT ratios are as follows:
2.1. VBase considered is 400 kV
2.2. IBase considered is 3000 A and the calculations are done considering CT
ratio as 3000 A/1 A and VT ratio as 400 kV/110 V
2.3. Rated frequency = 50 Hz
3. Set the constant input voltage as, VA = 63.5∠0° V, VB = 63.5∠240° V, and VC = 63.5∠120° V in
secondary at rated frequency.
4. Set the constant input current as, IA = 0∠0° A, IB = 0∠ 240° A, and IC = 0∠120° A in secondary at
rated frequency.
5. Following are the steps need to be followed to check the operation of Step 1:
Step
No.
Step1 operating characteristic verification Expected output
5-a Inject constant voltages of VA = 1.0∠0° V, VB= 0∠240° V, VC =
0∠120° V and constant currents of IA = 0.10∠0° A, IB = 0∠240° A,
IC = 0∠120° A in secondary at rated frequency.
PU_ST1 and BFI_3P signal
should be TRUE
Repeat Step 3 and Step 4, to reset PU_ST1 and BFI_3P.
5-b Inject constant voltages of VA = 57.73∠0° V, VB = 0∠240° V, VC =
0∠120° V and constant currents of IA = 1.10∠0° A, IB = 0∠240° A,
IC = 0∠120° A in secondary at rated frequency.
PU_ST1 and BFI_3P signal
should be TRUE
Repeat Step 3 and Step 4, to reset PU_ST1 and BFI_3P.
5-c Inject constant voltages of VA = 76.21∠0° V, VB = 0∠240° V, VC =
0∠120° V and constant currents of IA = 1.26∠0° A, IB = 0∠240° A,
IC = 0∠120° A in secondary at rated frequency.
PU_ST1 and BFI_3P signal
should be TRUE
6. Repeat Step 3, Step 4 and Step 5 for Step 2 operation, by setting Operation2 (Step 2) Enable, new
values of input currents as per slope characteristics and the VDepFact2 based on the I>> value;
check the output PU_ST2 and BFI_3P.
11.7.1.3 Completing the test
GUID-1F0146A2-2A0D-40D5-AC3C-2160810E9D06 v1
Continue to test another function or end the test by changing the TESTMODE setting to Disable. Restore
connections and settings to their original values, if they were changed for testing purposes.
11.7.2 Current unbalance protection of SCB, SCUCPTOC
GUID-1CF5256E-43B5-4D24-9A71-AB043413D681 v1
GUID-CEB4E17E-DBDC-4201-BDC2-043E6F73BCD6 v1
Prepare the IED for verification of settings outlined in
Section 10.1.2.
11.7.2.1 Verifying the signals and settings
Operation modes
GUID-8F767261-9D2D-49A7-87E0-CFEDF998FA66 v1
A shunt capacitor current unbalance protection (SCUCPTOC) function can be operated in two different
modes based on the physical connection and configuration of the capacitor bank.
Section 11 1MRK 504 165-UUS Rev. J
Testing functionality by secondary injection
216 Transformer protection RET670
Commissioning manual
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