ABB REC650 - Page 180

IEC08000013-3-en.vsd
UN ST1
TR1
ST2
TR2
START
TRIP
Comparator
UN > U1>
Start
&
Trip
Output
Logic
Step 2
Phase 1
Phase 1
Timer
t2
START
Start
&
Trip
Output
Logic
Step 1
Time integrator
or Timer t1
Comparator
UN > U2>
START
TRIP
TRIP
OR
OR
IEC08000013 V3 EN
Figure 75: Schematic design of Two step residual overvoltage protection
(ROV2PTOV)
The design of Two step residual overvoltage protection
(ROV2PTOV) is schematically described in Figure 75. UN is a signal
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.
Section 7 1MRK 511 287-UEN A
Voltage protection
174
Technical manual