ABB REG670 Applications Manual page 368

Section 9
Current protection
362
The residual power, measured by the sensitive earth fault protections in A and B will
be:
= ×
S 3U 3I
0 A 0 A 0
EQUATION1951 V1 EN
= ×
S 3U 3I
0 B 0 B 0
EQUATION1952 V1 EN
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 3U 3I cos
0 A ,prot 0 A 0
EQUATION1953 V1 EN
= × ×
S 3U 3I cos
0 B,prot 0 B 0
EQUATION1954 V1 EN
The angles φ and φ are the phase angles between the residual current and the
A B
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:
× × × j
kSN (3I 3U cos (reference))
0 0
=
t
inv
× × j
3I 3U cos (measured)
0 0
EQUATION1942 V2 EN
The function can be set On/Off with the setting of Operation.
Common base IED values for primary current (IBase), primary voltage (UBase) and
primary power (SBase) are set in a Global base values for settings function
GBASVAL.
GlobalBaseSel: It is used to select a GBASVAL function for reference of base values.
RotResU: It is a setting for rotating the polarizing quantity ( 3U
This parameter is set to 180 degrees by default in order to inverse the residual voltage
( 3U ) to calculate the reference voltage (-3U
0
is used as the polarizing quantity for directionality, it is important to set this parameter
correctly.
With the setting OpMode the principle of directional function is chosen.
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
j
A
j
B
-jRCADir
e
0
1MRK 502 071-UEN -
(Equation 203)
(Equation 204)
(Equation 205)
(Equation 206)
(Equation 207)
) by 0 or 180 degrees.
0
). Since the reference voltage
Application manual