ABB ret650 - Page 221

START
ST1L1
ST1L2
ST1L3
ST1
T R
1
START
S T 2
T R
2
S
T A
R T
TRIP
IEC08000012-3-en.vsd
Comparator
U > U1>
Comparator
U > U1>
Comparator
U> U1>
MaxVoltSelect
Comparator
U> U2>
Comparator
U> U2>
Comparator
U > U2>
Start
&
Trip
Output
Logic
Step 1
Start
&
Trip
Output
Logic
Step 2
Phase 3
Phase 2
Phase 1
Phase 3
Phase 2
Phase 1
Timer
t2
Voltage Phase
Selector
OpMode2
1 out of 3
2 outof 3
3 out of 3
Time integrator
Timer t1
Voltage Phase
Selector
OpMode1
1 out of 3
2 outof 3
3 out of 3
TRIP
TRIP
OR
OR
OR
OR
OR
OR
UL1 or UL12
UL2 or UL23
UL3 or UL31
IEC08000012 V3 EN
Figure 95: Schematic design of Two step overvoltage protection (OV2PTOV)
1MRK 504 135-UEN A Section 9
Voltage protection
215
Technical manual