ABB RELION REX640 Technical Manual page 969

1MRS759142 C
REX640
Technical Manual
Measurement mode setting
PhsA
PhsB
PhsC
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 the
combination of the settings Directional mode and Power angle. The selectable
options for the Directional mode setting are "Forward" and "Reverse". The Power
angle setting can be used to set the power direction between the reactive and active
power.
A typical error is, for example, that the VT or CT poles are wrongly
connected. This is seen as a power flow opposite to that of the intended
direction. The Pol Reversal setting can be used to correct the situation.
By setting the value to "True", the measured apparent power is turned
180 degrees.
Protection functions
Power calculation
*
S U I
3
= ⋅ ⋅
a a
P Re S
( )
=
*
S 3 U I
= ⋅ ⋅
b b
P Re S
( )
=
*
S 3 U I
= ⋅ ⋅
c c
P Re S
( )
=
Section 4
963