ABB Relion 670 Series Applications Manual page 165

1MRK 511 358-UUS A
=
3I
0
2 Z
EQUATION2023-ANSI V1 EN-US
Where
V
phase
Z
1
Z
0
R
f
The residual voltages in stations A and B can be written:
=
V 3I (Z
0 A
EQUATION2024-ANSI V1 EN-US
=
V 3I (Z
OB
EQUATION2025-ANSI V1 EN-US
The residual power, measured by the sensitive ground fault protections in A and B will be:
=
S 3V
0A
EQUATION2026-ANSI V1 EN-US
=
S 3V
0B
EQUATION2027-ANSI V1 EN-US
The residual power is a complex quantity. The protection will have a maximum sensitivity in the
characteristic angle RCA. The apparent residual power component in the characteristic angle,
measured by the protection, can be written:
S
0 A ,prot
EQUATION2028-ANSI V1 EN-US
=
S
0 B,prot
EQUATION2029-ANSI V1 EN-US
The angles φ
the station compensated with the characteristic angle RCA.
Application manual
3V
phase
× + + ×
Z 3 R
1 0 f
is the phase voltage in the fault point before the fault
is the total positive sequence impedance to the fault point. Z
is the total zero sequence impedance to the fault point. Z
is the fault resistance.
× +
3R )
0 T ,0 N
× + +
3R Z
0 T ,0 N lineAB,0
×
3I
0A 0
×
3I
0B 0
= × × j
3V 3I cos
0 A 0 A
× × j
3V 3I cos
0 B 0 B
and φ are the phase angles between the residual current and the residual voltage in
A B
= Z
0
)
= Z +Z +Z +Z
1 sc T,1 lineAB,1 lineBC,1
+3R +Z +Z
T,0 N lineAB,0 lineBC,0
Section 7
Current protection
(Equation 51)
(Equation 52)
(Equation 53)
(Equation 54)
(Equation 55)
(Equation 56)
(Equation 57)
159