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Section 10
Testing functionality by secondary injection
6.
Inject these two currents into the IED. Observe that differential function shall be stable. Write
down the service values for incoming and differential currents for the phase L1. Observe that
differential current should be very small.
7.
Switch off the currents.
8.
Repeat the same test procedure for the phases L2 and L3.
9.
Repeat above test steps for all used CT inputs (i.e. 2 ≤ x ≤ Nmax,where Nmax is the maximum
number of used CT inputs).
10.3.1.4
Operation of fast open CT detection algorithm
For fast open CT test two current inputs shall always be used. Similar to the previous section, the
test will be explained for CT1 and CTx (2 ≤ x ≤ Nmax).
The connections are shown for phase L1 only. Similar connection shall be used for testing phase L2
and L3 also. The typical connection between the three-phase current test set and the IED for this
type of tests is shown in Figure 13.
Follow the following test instructions to perform the test on the operation of fast open CT detection.
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) from the previous section.
4.
Set the current I2 (that is, connected to current input CTx) to the value calculated by the
formula (Equation 2) from the previous section.
5.
Make sure there is enough current for fast open CT algorithm to operate, when the current is
disconnected later during testing, by checking that the value of the product I2 × CTprimx is
bigger than the value of the product 1.1 × OCTOperLev
6.
Set the phase angle of the current I2 as explained in the previous section.
7.
Inject these two currents into the IED for approximately 5s. Observe that the differential function
shall be stable. Write down the service values for incoming and differential currents for phase
L1. Observe that the differential current should be very small.
8.
Switch off the current I1 only (that is, set its magnitude back to 0A).
9.
Check that open CT condition shall be detected by the IED, and the differential function
behavior shall be in accordance with the value of the parameter FastOCTOper.
10.
Check that open CT alarm contacts operate accordingly to the scheme wiring.
11.
Check that open CT information is stored in the event list (if connected).
12.
Switch off the currents.
13.
Reset the open CT blocking in the reset menu of the local HMI.
14.
Check that open CT reset information is stored in the event list (if connected).
15.
Repeat the same test procedure for the phases L2 and L3.
10.3.1.5
Operation of slow open CT detection algorithm
For open CT test two current inputs shall be always used. Similar to the previous section, the test will
be explained for CT1 and CTx (2 ≤ x ≤ Nmax).
The connections are shown for phase L1 only. Similar connection shall be used for testing phase L2
and L3 also. The typical connection between the three-phase current test set and the IED for this
type of tests is shown in Figure 13.
Follow the following test instructions to perform the test on the operation of slow open CT detection:
76
© 2017 - 2022 Hitachi Energy. All rights reserved
1MRK 505 372-UEN Rev. K
SEMOD65869-3 v4
SEMOD65871-3 v4
Busbar protection REB670
Commissioning manual
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