ABB RELION 620 Series Technical Manual page 368

Section 4
Protection functions
362
Table 299: Power calculation
Measurement mode setting
PhsA, PhsB, PhsC
Arone
Pos Seq
PhsAB
PhsBC
PhsCA
PhsA
PhsB
PhsC
If all three phase voltages and phase currents are fed to the protection
relay, the positive-sequence alternative is recommended (default).
Depending on the set Measurement mode, the power calculation calculates active power,
reactive power and apparent power values from the available set of measurements. The
calculated powers S, P, Q and the power factor angle, PF_ANGL, are available in the
Monitored data.
Directional calculation
The Directional calculation determines the direction of the measured power. The
measured power is considered to be in the forward direction if the active power is positive,
else it is considered to be in the reverse direction.
If the polarity of the measured power is opposite to normal, the correction can be done by
setting Pol reversal to "Yes", which rotates the apparent power by 180 degrees.
Level detector
The Level detector compares the calculated value of the active power with a set Start
value. If the calculated value of the active power falls below Start value in the forward
direction or if the measured power is in the reverse direction, the Level detector enables
the Timer module.
Power calculation
U_A, U_B, U_C, I_A, I_B, I_C
U_AB, U_BC, I_A, I_C
{U_A, U_B, U_C} or {U_AB, U_BC, U_CA} and I_A,
I_B, I_C
U_AB, I_A, I_B
U_BC, I_B, I_C
U_CA, I_C, I_A
U_A, I_A
U_B, I_B
U_C, I_C
1MAC504801-IB E
620 series ANSI
Technical Manual