ABB RES670 Technical Manual page 524

Section 16
Monitoring
518
Set value for Formula used for complex, three-
parameter phase power calculation
"Mode"
8 B
= ×
S 3
EQUATION1575 V1 EN-US
9 C
= ×
S 3
EQUATION1577 V1 EN-US
* means complex conjugated value
It shall be noted that only in the first two operating modes that is, 1 & 2 the
measurement function calculates the three-phase power accurately. In other operating
modes that is, from 3 to 9 it calculates the three-phase power under assumption that the
power system is fully symmetrical. Once the complex apparent power is calculated
then the P, Q, S, & PF are calculated in accordance with the following formulas:
=
P Re( ) S
EQUATION1403 V1 EN-US
=
Q Im( ) S
EQUATION1404 V1 EN-US
= = 2 + 2
S S P Q
EQUATION1405 V1 EN-US
P
j
= =
PF cos
S
EQUATION1406 V1 EN-US
Additionally to the power factor value, the two binary output signals from the function
are provided which indicates the angular relationship between the current and voltage
phasors. Binary output signal ILAG is set TRUE when current phasor is lagging
behind voltage phasor. Binary output signal ILEAD is set TRUE when current phasor
is leading the voltage phasor.
Formula used for voltage and
current magnitude calculation
× V
*
V I
B B
(Equation 78)
=
I
EQUATION1576 V1 EN-US
× * V
V I
C C
(Equation 80)
=
I
EQUATION1578 V1 EN-US
1MRK 511 408-UUS A
Comment
Used when only
= × V
3 V
B
B ground voltage is
available
I
B
(Equation 79)
Used when only
= × V
3 V
C
C
ground voltage is
available
I
C
(Equation 81)
Phasor measurement unit RES670 2.2 ANSI
Technical manual
phase-to-
phase-to-
(Equation 82)
(Equation 83)
(Equation 84)
(Equation 85)