ABB Relion Technical Manual page 299

1MRK 502 048-UUS A
Technical manual
value, and the highest voltage is used for the inverse time characteristic integration. A
special logic is included to achieve the 1 out of 3, 2 out of 3 or 3 out of 3 criteria to fulfill the
PICKUP condition. The design of Two step overvoltage protection (OV2PTOV, 59) is
schematically described in
Comparator
VA or VAB
V > Pickup1
Comparator
VB or VBC
V > Pickup1
Comparator
VC or VCA
V > Pickup1
MaxVoltSelector
Comparator
V > Pickup2
Comparator
V > Pickup2
Comparator
V > Pickup2
ANSI08000012 V3 EN
Figure 135: Schematic design of Two step overvoltage protection (OV2PTOV, 59)
Figure 135.
Phase A
Voltage Phase
Selector
OpMode1
Phase B
1 out of 3
2 outof 3
Pickup
Phase C
3 out of 3
&
Trip
Output
Logic
PICKUP
Step 1
Time integrator
TRIP
or Timer t1
Phase A
Voltage Phase
Selector
OpMode2
Phase B
1 out of 3
2 outof 3
Pickup
Phase C
3 out of 3
&
Trip
Output
Logic
PICKUP
Step 2
Timer
TRIP
t2
Section 9
Voltage protection
PU_ST1_A
PU_ST1_B
PU_ST1_C
PU_ST1
OR
OR
OR
OR
PICKUP
OR
TRIP
OR
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