ABB Relion 670 series, Technical Reference Manual

Page: 837 / 1232

Power factor is a ratio of active power to apparent power. The function calculates
power factor from the calculated values of active power and apparent power of A, B
and C loop by following equation:
A
A
A
pf
P
S
=
EQUATION2246-ANSI V1 EN
(Equation 152)
B
B
B
pf
P
S
=
EQUATION2247-ANSI V1 EN
(Equation 153)
C
C
C
pf
P
S
=
EQUATION2248-ANSI V1 EN
(Equation 154)
Active power trip mode
The low active power functionality has a trip mode setting. According to this setting,
trip is activated if the low active power is detected in one out of three phases or two out
of three phases respectively. These two modes are user settable through setting
OpModeSel .
Zero clamping filtering
The function will do zero clamping to disable the calculation if the current and voltage
values of a particular phase are less than 30% of
VBase for voltage and 3% of IBase for
current value.
Calculation
The active power setting value used for detection of under power must be given as a three-
phase value. The design starts to calculate internally the per phase value from this
setting and detect phase wise under power condition individually. The power factor
pickup value is common for all the three phases.
Phase wise analog values apparent power, active power, reactive power and power
factor are available as service values.
1MRK505222-UUS C
Section 13
Scheme communication
831
Technical reference manual