ABB Relion Technical Manual page 304

Section 9
Voltage protection
298
VN Comparator
VN > Pickup1
Time integrator
or Timer t1
Comparator
VN > Pickup2
Timer
t2
ANSI08000013 V2 EN
Figure 137: Schematic design of Two step residual overvoltage protection
(ROV2PTOV, 59N)
The design of Two step residual overvoltage protection (ROV2PTOV,
59N) is schematically described in
the three phase group signal V3P which shall be connected to output AI3P
of the SMAI. If a connection is made to the 4 input GRPx_N (x is equal to
instance number 2 to 12) on the SMAI, VN is this signal else VN is the
vectorial sum of the three inputs GRPx_A to GRPx_C.
Phase 1
Pickup
PICKUP
&
Trip
Output
Logic
TRIP
Step 1
Phase 1
Pickup
PICKUP
&
Trip
Output
Logic
TRIP
Step 2
1MRK 502 048-UUS A
PU_ST1
TRST1
PU_ST2
TRST2
PICKUP
OR
OR
ANSI08000013-2-en.vsd
Figure 137. VN is a signal included in
Technical manual
TRIP