ABB RELION 620 Series Technical Manual page 359

1MAC504801-IB E
620 series ANSI
Technical Manual
I_A
I_B
I3P
I_C
I1
U_A
U_B
U_C
U_AB
U3P
U_BC
U_CA
U1
BLOCK
BLK_TRIP
BLK_PICKUP
FR_TIMER
GUID-7AABB604-0901-4815-841F-352961249261 V1 EN
Figure 161: Functional module diagram
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 292: Voltages and currents used in apparent 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.
Level
detector
Power
calculation
Directional
calculation
Voltage and currents used in 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_BU_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,IC
Section 4
Protection functions
Timer
TRIP
t
PICKUP
353