Matrix with Zero Sequence
Reduction set to On
Matrix with Zero Sequence
Reduction set to Off
Matrix for winding with 120°
leading
1 2 1
1
1 1 2
3
2 1 1
- -
× - -
- -
é ù
ê ú
ê ú
ê ú
ë û
EQUATION1239 V1 EN (Equation 15)
0 1 0
0 0 1
1 0 0
é ù
ê ú
ê ú
ê ú
ë û
EQUATION1240 V1 EN (Equation 16)
Matrix for winding with 90°
leading
0 1 -1
1
-1 0 1
3
1 1 0
×
-
é ù
ê ú
ê ú
ê ú
ë û
EQUATION1241 V1 EN (Equation 17)
Not applicable. Matrix on the
left used.
Matrix for winding with 60°
leading
1 1 2
1
2 1 1
3
1 2 1
-
× -
-
é ù
ê ú
ê ú
ê ú
ë û
EQUATION1242 V1 EN (Equation 18)
0 0 1
1 0 0
0 1 0
-
-
-
é ù
ê ú
ê ú
ê ú
ë û
EQUATION1243 V1 EN (Equation 19)
Matrix for winding with 30°
leading
1 0 -1
1
-1 1 0
3
0 1 1
×
-
é ù
ê ú
ê ú
ê ú
ë û
EQUATION1244 V1 EN (Equation 20)
Not applicable. Matrix on the
left used.
By using this table complete equation for calculation of fundamental frequency
differential currents for two winding power transformer with YNd5 vector group and
enabled zero sequence current reduction on HV side will be derived. From the given
power transformer vector group the following is possible to be concluded:
1. The HV star (Y) connected winding will be used as the reference winding and
zero sequence currents shall be subtracted on that side
2. The LV winding is lagging for 150°
With the help of table
47, the following matrix equation can be written for this power
transformer:
1 2 1 1 1_ 1 1 0 1 1_ 2
1 _ 2 1
2 1 2 1 2_ 1 1 1 0 2_ 2
3 _ 1
3
3 1 1 2 3_ 1 0 1 1 3_ 2
IDL IL W IL W
Ur W
IDL IL W IL W
Ur W
IDL IL W IL W
- - -
é ù é ù é ù é ù é ù
ê ú ê ú ê ú ê ú ê ú
= × - - × + × × - ×
ê ú ê ú ê ú ê ú ê ú
ê ú ê ú ê ú ê ú ê ú
- - -
ë û ë û ë û ë û ë û
EQUATION2015 V1 EN (Equation 21)
where:
IDL1 is the fundamental frequency differential current in phase L1 (in W1 side primary amperes)
IDL2 is the fundamental frequency differential current in phase L2 (in W1 side primary amperes)
IDL3 is the fundamental frequency differential current in phase L3 (in W1 side primary amperes)
Table continues on next page
1MRK502052-UEN B Section 6
Differential protection
119
Technical manual
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