ABB REG670 Applications Manual page 149

1MRK 502 071-UEN -
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual
To ensure proper application of the IED for this power transformer it is necessary to
do the following:
1. Check that HV & LV CTs are connected to 5 A CT inputs in the IED.
2. For second solution make sure that LV delta connected CTs are DAB connected.
3. For star connected CTs make sure how they are 'star'red (that is, earthed) to/from
protected transformer.
4. Enter the following settings for all three CT input channels used for the HV side
CTs, see table 18.
Table 18: CT input channels used for the HV side CTs
Setting parameter
CTprim
CTsec
CTStarPoint
5. Enter the following settings for all three CT input channels used for the LV side
CTs, see table "CT input channels used for the LV side
CT input channels used for the LV side CTs
Setting parameter
CTprim
CTsec
CTStarPoint
To compensate for delta connected CTs, see equation 18.
6. Enter the following values for the general settings of the differential protection
function, see table19.
Table 19: General settings of the differential protection
Setting parameter
RatedVoltageW1
Rated VoltageW2
RatedCurrentW1
RatedCurrentW2
Table continues on next page
Selected value for both solutions
400
5
ToObject
Selected value for Solution 1 (star
connected CT)
1500
5
ToObject
selected value for both Solution 1
(star conected CT)
115 kV
24.9 kV
301 A
1391 A
Section 7
Differential protection
CTs".
Selected value for Solution 2
(delta connected CT)
1500
=
866
3
(Equation 18)
EQUATION1889 V1 EN
5
ToObject
Selected value for both Solution
2 (delta connected CT)
115 kV
24.9 kV
301 A
1391 A
143