ABB RET650 Technical Manual page 226

Section 9
Voltage protection
220
UN Comparator
UN > U1>
Time integrator
or Timer t1
Comparator
UN > U2>
Timer
t2
IEC08000013 V3 EN
Figure 97: Schematic design of Two step residual overvoltage protection
(ROV2PTOV)
The design of Two step residual overvoltage protection
(ROV2PTOV) is schematically described in
included in the three phase group signal U3P which shall be connected
to output AI3P of the SMAI. If a connection is made to the 4 input
GRPxN (x is equal to instance number 2 to 12) on the SMAI, UN is
this signal else UN is the vectorial sum of the three inputs GRPxL1 to
GRPxL3.
Phase 1
Start
START
&
Trip
Output
Logic
TRIP
Step 1
Phase 1
Start
START
&
Trip
Output
Logic
TRIP
Step 2
1MRK 504 135-UEN A
ST1
TR1
ST2
TR2
START
OR
TRIP
OR
IEC08000013-3-en.vsd
Figure 97. UN is a signal
Technical manual