Operation Of Fast Open Ct Detection Algorithm - ABB Relion 670 Series Commissioning Manual

Section 10
Testing functionality by secondary injection
The test will be explained for CT1 and one general current input CTx (2 ≤ x ≤ Nmax, where Nmax is the
maximum number of used CT inputs).
Follow the following test instructions to perform the stability test:
1. Connect the currents I1 and I2 from the three-phase test set to the current terminals of CT1 and
CTx inputs of the IED as shown in Figure 13.
2. Make sure that current measurement from CT1 and CTx inputs are included into the same
differential zone (see the previous test instruction for more details).
3. Set the current I1 (that is, the current connected to the reference current input CT1) to the nominal
secondary value (normally 1A or 5A) at 0°,
I 
1 CTsec1
IECEQUATION16064 V1 EN-US
where the configuration parameter CTsec1 represents the rated secondary current of the current
input CT1.
4. Set the current I2 (that is, the current connected to the current input CTx) to the value calculated as
follows:
I 2 CTsecx
IECEQUATION16065 V1 EN-US
Where
secondary current of the current input CTk, while the configuration parameter CTprimk represents
the rated primary current.
5. Set the phase angle of the current I2 to 180°, if both current inputs (that is, CT1 and CTx) have the
same set value for TRM parameter CTStarPointx (i.e. both set to value ToObject or both set to
value FromObject). Set the phase angle of the current I2 to 0°, otherwise.
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 A. Observe that differential
current should be very small.
7. Switch off the currents.
8. Repeat the same test procedure for the phases B and C.
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 A only. Similar connection shall be used for testing phase B and C
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.
74
CTx
  
ratio
CT 1
ratio
CTprimk ,

CTk k
ratio
CTseck
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CTprimx

CTsec1 ,
CTprim1
 or x
1
. The configuration parameter CTseck represents the rated
1MRK 505 372-UUS Rev. K
(Equation 1)
(Equation 2)
SEMOD65869-3 v4
Busbar protection REB670
Commissioning manual