ABB RELION REX640 - Page 655

Winding selection setting defines the protection relay location respect to the
transformer. If the protection relay is situated at the HV side of the transformer,
then protection relay location setting is set to “Winding 1” and respectively to
“Winding 2” if protection relay is situated at the LV side. If the differential protection
relays are used to protect a line without in-zone transformer, then the setting is set
to “Not in use”. In this case vector group matching is ignored.
The matching of the phase difference is based on the phase shifting and
the numerical delta connection inside the protection relay. The Winding 1 type
parameter determines the connection on winding 1 (“Y”, “YN”, “D”, “Z”, “ZN”). The
vector group matching can be implemented either on both, winding 1 and winding 2,
or only on winding 1 or winding 2, at intervals of 30° with the Clock number setting.
Similarly, the Winding 2 type parameter determines the connections of the phase
windings on the low voltage side (“y”, “yn”, “d”, “z”, “zn”).
When the vector group matching is Yy0 and the CT connection type is according to
“Type 2”, the phase angle of the phase currents connected to the protection relay
does not change. When the vector group matching is Yy6, the phase currents are on
one side turned 180° in the protection relay.
Example 1, vector group matching of an YNd11-connected power transformer on
winding 1, CT connection type according to type 1. The Winding 1 type setting is
“YN”, Winding 2 type is “d” and Clock number is “Clk Num 11”. This is compensated
internally by giving winding 1 internal compensation value +30° and winding 2
internal compensation value 0°:
I
I I
L mHV
L L
−
− −
=
−
1
1 2
3
(Equation 146)
I
I I
L mHV
L L
−
−−
=
−
2
2 3
3
(Equation 147)
I
I I
L mHV
L L
−
− −
=
−
3
3 1
3
(Equation 148)
Example 2, if vector group is Yd11 and CT connection type is according to type 1, the
compensation is a little different. The Winding 1 type setting is “Y”, Winding 2 type
is “d” and Clock number is “Clk Num 11”. This is compensated internally by giving
winding 1 internal compensation value 0° and winding 2 internal compensation value
-30°:
I
I I
L mLV
L L
−
− −
=
−
1
1 3
3
(Equation 149)
1MRS759142 F
Protection functions
REX640
Technical Manual
655