• 1 Unbalance Curr - Select this option using the parameter setting SCBConf, if one unbalance
current is connected to the function.
• 3 Unbalance Curr - Select this option using the parameter setting SCBConf, if three unbalance
currents are connected to the function.
Ensure that mandatory three-phase currents and unbalance currents are connected to
the separate SMAI blocks and their outputs are connected to the I3P and I3UNB inputs
of the SCUCPTOC function.
Testing with 1 Unbalance Curr option
GUID-201EB341-DD91-4927-A8BB-4A873E1798DB v1
1. Set IBase1 as primary phase current and IBase2 as primary unbalance current using the setting
function GBASVAL.
2. Set the following parameters:
• Operation = ON
• SCBConf = 1 unbalance curr
• tDefTrip = 5.00 s; tDefAlm = 5.00 s; tDefWrn = 5.00 s
• IUnbal> = 30% IB2
• IUnbalAlm> = 20% IB2
• IUnbalWrn> = 10% IB2
• IMin = 10% IB1
3. Activate the RESETCOMP input to ensure that the stored values are reset to zero.
4. The logical signals and service values for SCUCPTOC function are available on the local HMI under:
Main menu/Tests/Function status/Unbalance protection /CapBankCurrentUnbalance(60N,
Iub>)/SCUCPTOC(60N, Iub>):x/outputs , where x = instance number.
5. To store the unbalance current values, perform these steps:
Step No.
Changes after step 3 Expected output
5-a Inject constant currents* of I
A
= 1∠0° A, I
B
=
1∠240° A, and I
C
= 1∠120° A in secondary at
rated frequency.
since SCBConf = 1 unbalance curr
IA should show 1000 A
IB and IC should show 0 A
5-b Inject I
UNBˍA
= 0.2∠0° A in secondary at rated
frequency
IUNB_A and IUNBCLC_A should show 2 A
5-c** Activate binary input TRIGCOMP for 1 s • The output COMPEXED should become
HIGH for 100 ms
• The output LASTCOMP should display the
date and time of compensation
The following outputs should show the mentioned
values:
• IMEMˍA = 1000 A
• IMEMUNBˍA = 2 A
• IREFUNBˍA = 2 A
• IUNBCLCˍA = 0 A
* - CT ratios of the phase currents (1000/1 A) and unbalance currents (10/1 A). The values of IB1 and IB2 are
considered as 1000 A and 10 A, respectively. The current inputs I
A
, I
B
, and I
C
refer to the phase current inputs and
I
UNBˍA
refer to the unbalance current inputs.
** - This step should be done only during Factory Acceptance Test (FAT). At field, the testing should be done with
the stored field values.
6. Check the respective operation of warning, alarm, and trip.
1MRK 504 165-UUS Rev. J Section 11
Testing functionality by secondary injection
Transformer protection RET670 217
Commissioning manual
© 2017 - 2021 Hitachi Power Grids. All rights reserved
To Next Page
Loading...
