ABB Relion REC670, Applications Manual

Page: 202 / 658

0A 0 T,0 N
V 3I (Z 3R )
= × +
EQUATION2024-ANSI V1 EN-US
(Equation 52)
OB 0 T ,0 N lineAB,0
V 3I (Z 3R Z )
= × + +
EQUATION2025-ANSI V1 EN-US
(Equation 53)
The residual power, measured by the sensitive ground fault protections in A and B will
be:
0A 0A 0
S 3V 3I
= ×
EQUATION2026-ANSI V1 EN-US
(Equation 54)
0B 0B 0
S 3V 3I
= ×
EQUATION2027-ANSI V1 EN-US
(Equation 55)
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:
0A,prot 0A 0 A
S 3V 3I cos
= × × j
EQUATION2028-ANSI V1 EN-US
(Equation 56)
0B,prot 0 B 0 B
S 3V 3I cos
= × × j
EQUATION2029-ANSI V1 EN-US
(Equation 57)
The angles φ
A
and φ
B
are the phase angles between the residual current and the
residual voltage in the station compensated with the characteristic angle RCA.
The protection will use the power components in the characteristic angle direction for
measurement, and as base for the inverse time delay.
The inverse time delay is defined as:
0 0
inv
0 0
TDSN (3I 3V cos (reference))
t
3I 3V cos (measured)
f
f
× × ×
=
×
EQUATION2069 V1 EN-US
(Equation 58)
The function can be set Enabled/Disabled with the setting of Operation .
Section 8
1MRK 511 401-UUS A
Current protection
196 Bay control REC670 2.2 ANSI
Application manual