ABB RELION REX640 Technical Manual page 809

1MRS759142 C
REX640
Technical Manual
equipment. The leakage reactance of the transformer or generator is set through the
Leakage React setting in percentage of the Z base.
The internal induced voltage (E) is calculated from the measured voltage. The settings
Voltage selection and Phase supervision determine which voltages and currents are to
be used. If the Voltage selection setting is set to "phase-to-earth" or "phase-to-phase",
the Phase supervision setting is used for determining which phases or phase-to-phase
voltages ("A or AB", "B or BC" and "C or CA") and currents are to be used for the
calculation of the induced voltage.
Table 766: Voltages and currents used for induced voltage (emf) E calculation
Voltage selection Phase supervision
setting setting
phase-to-earth A or AB
phase-to-earth B or BC
phase-to-earth C or CA
phase-to-phase A or AB
phase-to-phase B or BC
phase-to-phase C or CA
Pos sequence N/A
1) Voltages, currents and the leakage reactance X
ohms.
If all three phase or phase-to-phase voltages and phase currents are fed
to the protection relay, the positive-sequence alternative is
recommended.
If the leakage reactance of the protected equipment is unknown or if
the measured voltage (U
calculation, then by setting the leakage reactance value to zero the
calculated induced voltage (E) is equal to the measured voltage.
Protection functions
Calculation of internal induced voltage (emf) E
E 3 U I ( j X
(
= ⋅ + ⋅ ⋅
A A leak
GUID-07155EC6-9E4D-43E5-B84C-89F5D97EA1C1 V1 EN
E 3 U I ( j X
(
= ⋅ + ⋅ ⋅
B B leak
GUID-F1C60C86-3CA1-4240-A93B-E93B2DDE338C V1 EN
E 3 U I ( j X
(
= ⋅ + ⋅ ⋅
C C leak
GUID-95435236-BF08-4F72-98F9-FDB985DC1959 V1 EN
E U ( I I ) ( j X
(
= + − ⋅ ⋅
AB A B
GUID-61FA1D12-C6EB-429B-9B35-41F81A512F8F V1 EN
E U ( I I ) ( j X
(
= + − ⋅ ⋅
BC B C
GUID-F646A0E7-1088-487B-AB29-C5425080E7F9 V1 EN
E U I I j X
( ) (
(
= + − ⋅ ⋅
CA C A
GUID-4D70833A-2141-4A11-8125-BF1E49DBF38F V1 EN
E U I j X
3 (
(
= ⋅ + ⋅ ⋅
leak
1 1
GUID-327295CF-0E2E-4282-B10A-A3B13550782A V1 EN
in the calculations are given in volts, amps and
leak
) is to be used in the excitation level
m
Section 4
1)
)
)
(Equation 194)
)
)
(Equation 195)
)
)
(Equation 196)
)
)
leak
(Equation 197)
)
)
leak
(Equation 198)
)
)
leak
(Equation 199)
)
)
(Equation 200)
803