ABB RELION REX640 - Page 1065

Measurement mode setting Power calculation
Pos Seq
S U I= ⋅ ⋅3
1 1
*
P S=
( )
Re
PhsAB
S U I I
ab a b
= ⋅ ⋅ −
( )
3
* *
P S=
( )
Re
PhsBC
S U I I
bc b c
= ⋅ ⋅ −
( )
3
* *
P S=
( )
Re
PhsCA
S U I I
ca c a
= ⋅ ⋅ −
( )
3
* *
P S=
( )
Re
PhsA
S U I
a a
= ⋅ ⋅3
*
P S=
( )
Re
PhsB
S U I
b b
= ⋅ ⋅3
*
P S=
( )
Re
PhsC
S U I
c c
= ⋅ ⋅3
*
P S=
( )
Re
If all three phase voltages and phase currents are fed to the protection
relay, the positive-sequence alternative is recommended.
The calculated powers S, P, Q and the power factor angle PF_ANGL are available in
the Monitored data view.
Level detector
The Level detector compares the magnitude of the measured apparent power to the
set Start value . If the measured value exceeds the set Start value , the Level detector
sends an enabling signal to the Timer module.
Directional calculation
The Directional calculation module monitors the direction of the apparent power.
When the apparent power flow is in the operating area, the module sends the
enabling signal to the Timer module. The directional operation can be selected with
1MRS759142 F
Protection functions
REX640
Technical Manual
1065