ABB 615 series Technical Manual page 732

Section 4
Protection functions
726
Power calculation
This module calculates the apparent power based on the selected voltages and currents.
The Measurement mode setting determines which voltages and currents are used. It is also
possible to use positive-sequence components for calculating the apparent power which
makes the determination of power insensitive to a possible asymmetry in currents or
voltages and corresponds to the real load on the prime mover of the generator.
Table 629: Power calculation
Measurement mode setting
PhsA, PhsB, PhsC
Arone
Pos Seq
PhsAB
PhsBC
PhsCA
PhsA
PhsB
PhsC
Power calculation
* *
S V I V I V
= ⋅ + + +
a b
a b
P Re S
( )
=
* *
S V I V I
= ⋅ − ⋅
ab bc
a c
P Re S
( )
=
*
S V I
3
= ⋅ ⋅
1
1
P Re S
( )
=
* *
( )
S 3 V I I
= ⋅ ⋅ −
ab
a b
P Re S
( )
=
* *
( )
S 3 V I I
= ⋅ ⋅ −
bc
b c
P Re S
( )
=
* *
S V ( I I )
3
= ⋅ ⋅ −
ca
c a
P Re S
( )
=
*
S 3 V I
= ⋅ ⋅
a
a
P Re S
( )
=
*
S V I
3
= ⋅ ⋅
b
b
P Re S
( )
=
*
S 3 V I
= ⋅ ⋅
c
c
P Re S
( )
=
1MAC059074-MB A
*
I
⋅
c
c
615 series ANSI
Technical Manual