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1MRK 505 372-UEN Rev. K
1.
Connect the currents I1 and I2 from the three-phase test set test set to the current terminals of
CT1 and CTx inputs of the IED as shown in Figure 13.
2.
Make sure that the current measurement from CT1 and CTx inputs are included into the same
differential zone (see the previous test instructions for more details).
3.
Set the current I1 (that is, current connected to input CT1) to the nominal secondary value
(normally 1A or 5A) at 0°, see the formula (Equation 1).
4.
Set the current I2(that is, connected to current input CTx) to the value calculate as follows:
I
IECEQUATION16067 V1 EN-US
Where
rated secondary current of the current input CTk, while the configuration parameter CTprimk
represents the rated primary current.
5.
Make sure there is enough current for slow open CT algorithm to operate, when the current is
disconnected later during testing, by checking that the value of the product 0.15 × I2 × CTprim1
is bigger than the value of OCTOperLev. If not, increase the current into CT1 input until this
condition is satisfied and change the current into input CTx accordingly.
6.
Set the phase angle of the current I2, as explained in the previous sections.
7.
Inject these two currents into the IED. Observe that the differential function shall be stable.
Write down the service values for incoming and differential currents for the phase L1. Observe
that the differential current should be approximately 15% of the incoming current.
8.
After pre-set time determined by parameter tSlow OCT, open CT condition shall be detected by
the IED. The differential function behavior shall be in accordance with the set value of the
parameter SlowOCTOper.
9.
Check that open CT alarm contacts operate accordingly to the scheme wiring.
10.
Check that open CT information is stored in the event list (if connected).
11.
Switch off the currents.
12.
Reset the open CT blocking in the reset menu of the local HMI.
13.
Check that open CT reset information is stored in the event list (if connected).
14.
Repeat the same test procedure for the phases L2 and L3.
10.3.1.6
Completing the test
Continue to test another function or end the test. Restore connections and settings to their original
values, if they were changed for testing purposes.
10.3.1.7
Check of trip circuits and circuit breakers
The trip circuits are tested as part of the secondary/primary injection test.
Check that the circuit breakers associated with the IED protection scheme operate when the tripping
outputs from the IEDs are activated. The trip outputs from the IEDs are conveniently activated by
secondary injection to activate a suitable protection function. Alternatively Forcing of Binary Output
Contacts from the IED under the Test Mode can be used.
10.4
Current protection
10.4.1
Directional phase overcurrent protection, four steps OC4PTOC
Prepare the IED for verification of settings outlined in Section
Busbar protection REB670
Commissioning manual
CTx
2 0.85 CTsecx
CT
CTprimk ,
CTk
ratio
CTseck
© 2017 - 2022 Hitachi Energy. All rights reserved
ratio
0.85 CTsec1
1
ratio
or x
k
1
. The configuration parameter CTseck represents the
Testing functionality by secondary injection
CTprimx
,
CTprim1
GUID-716ABD3A-301C-4E1B-A060-743E12CD3A96 v1
"Preparing the IED to verify
Section 10
(Equation 3)
SEMOD65863-3 v3
SEMOD53531-1 v1
SEMOD56287-67 v9
settings".
77
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