Operation Of Fast Open Ct Detection Algorithm - ABB REB670 Commissioning Manual

1MRK 505 372-UEN A
10.3.1.4
Busbar protection REB670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
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:
CTx
 
I 2 CTsecx
CT
IECEQUATION16065 V1 EN-US

CTk
Where
ratio
represents the rated 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 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).

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.
CTprimx
 
ratio
CTsec1
1 CTprim1
ratio
CTprimk ,
 or x
k 1
. The configuration parameter CTseck
CTseck
Section 10
(Equation 1)
,
(Equation 2)
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