ABB 615 Series - Page 703

U3P
I3P
Impedance
calculation
U_A
U_B
U_C
I_A
I_B
I_C
BLK_TRIP
External
loss
detection
EXT_LOS_DET
TRIP
PICKUP
I1
U1
Impedance
reach
check
t
Timer
BLOCK
BLK_PICKUP
U_AB
U_BC
U_CA
FR_TIMER
GUID-134FE243-96E9-4B5D-BEB2-75DB0AEE5FC5 V1 EN
Figure 346: Functional module diagram
Impedance calculation
This module calculates the apparent impedance based on the selected voltages and
currents. The Measurement mode and Phase Sel for Z Clc settings determine which
voltages and currents are to be used. If the Measurement mode is set to "1Phase-earth" or
"1Phase-phase", the Phase Sel for Z Clc setting is needed for determining which phase or
phase-phase voltages ("A or AB", "B or BC" and "C or CA") and currents should be used
for calculating the impedance.
Table 604: Voltages and currents used in impedance calculation
Measurement mode
Phase Sel for Z Clc Voltages and currents
1Phase-earth A or AB V_A, I_A
1Phase-earth B or BC V_B, I_B
1Phase-earth C or CA V_C, I_C
1Phase-phase A or AB V_AB, I_A, I_B
1Phase-phase B or BC V_BC, I_B, I_C
1Phase-phase C or CA V_CA, I_C, I_A
3Phase-earth N/A V_A, V_B, V_C, I_A, I_B, I_C
3Phase-phase N/A V_AB, V_BC, V_CA, I_A, I_B, I_C
Pos seqn N/A { V_A,V_B,V_C } or { V_AB,V_BC,V_CA } and I_A,
I_B, I_C
If all three phase voltages and phase currents are fed to the protection
relay, the positive-sequence alternative is recommended.
1MAC059074-MB A Section 4
Protection functions
615 series ANSI 697
Technical Manual