ABB REC670 Applications Manual page 192

Section 8
Current protection
186
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-US
= ×
S 3U 3I
0 B 0 B 0
EQUATION1952 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 3U 3I cos
0 A ,prot 0 A 0
EQUATION1953 V1 EN-US
= × ×
S 3U 3I cos
0 B,prot 0 B 0
EQUATION1954 V1 EN-US
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-US
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
degrees. This parameter is set to 180 degrees by default in order to inverse the
residual voltage ( 3U ) to calculate the reference voltage (-3U
0
reference voltage 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.
j
A
j
B
1MRK 511 401-UEN A
(Equation 54)
(Equation 55)
(Equation 56)
(Equation 57)
(Equation 58)
) by 0 or 180
0
-jRCADir
e ). Since the
0
Bay control REC670 2.2 IEC
Application manual