ABB REB650, Technical Manual

Page: 249 / 504

Set value for
parameter
“Mode”
Formula used for complex, three-
phase power calculation
Formula used for voltage and
current magnitude calculation
Comment
8 B
*
3
B B
S V I
= × ×
EQUATION1575 V1 EN
(Equation 49)
3
B
B
V V
I I
= ×
=
EQUATION1576 V1 EN
(Equation 50)
Used when only
V
B
phase-to-
ground voltage is
available
9 C
*
3
C C
S V I
= × ×
EQUATION1577 V1 EN
(Equation 51)
3
C
C
V V
I I
= ×
=
EQUATION1578 V1 EN
(Equation 52)
Used when only
V
C
phase-to-
ground voltage is
available
* means complex conjugated value
It shall be noted that only in the first two operating modes that is, 1 & 2 the
measurement function calculates exact three-phase power. 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:
Re( )
=
P S
EQUATION1403 V1 EN
(Equation 53)
Im( )
=
Q S
EQUATION1404 V1 EN
(Equation 54)
2 2 = = +
S S P Q
EQUATION1405 V1 EN
(Equation 55)
cos
P
PF
S
j
= =
EQUATION1406 V1 EN
(Equation 56)
Additionally to the power factor value the two binary output signals from the function
are provided which indicates the angular relationship between current and voltage
phasors. Binary output signal ILAG is set to one when current phasor is lagging behind
voltage phasor. Binary output signal ILEAD is set to one when current phasor is
leading the voltage phasor.
1MRK 505 277-UUS C
Section 12
Monitoring
243
Technical Manual