ABB Relion 670 Series Technical Reference Manual page 506

Section 8
Voltage protection
500
Comparator
VL1
VL1 < V1<
Comparator
VL2
VL2 < V1<
Comparator
VL3
VL3 < V1<
MinVoltSelector
Comparator
VL1 < V2<
Comparator
VL2 < V2<
Comparator
VL3 < V2<
MinVoltSelector
ANSI05000012 V2 EN
Figure 255: Schematic design of Two step undervoltage protection UV2PTUV (27)
Voltage Phase
Phase 1
Selector
OpMode1
Phase 2
1 out of 3
2 out of 3 Pickup
3 out of 3 t1
Phase 3
t1Reset
IntBlkStVal1
&
Trip
Output
PICKUP
Logic
Step 1
Time integrator
TRIP
tIReset1
ResetTypeCrv1
Voltage Phase
Phase 1
Selector
OpMode2
Phase 2
1 out of 3 Pickup
2 out of 3
t2
3 out of 3
Phase 3
t2Reset
&
IntBlkStVal2
Trip
Output
Logic
PICKUP
Step 2
Time integrator
TRIP
tIReset2
ResetTypeCrv2
1MRK505222-UUS C
ST1L1
ST1L2
ST1L3
ST1
OR
TR1L1
TR1L2
TR1L3
TR1
OR
ST2L1
ST2L2
ST2L3
ST2
OR
TR2L1
TR2L2
TR2L3
TR2
OR
PICKUP
OR
TRIP
OR
ANSI05000012-2-en.vsd
Technical reference manual