Sel 751A - Figure 4.19 Overvoltage Element Logic

4.32
SEL-751A Relay Instruction Manual Date Code 20100129
Protection and Logic Functions
Voltage-Based Protection
Figure 4.19 Overvoltage Element Logic
VAB or VA
VBC or VB
VCA or VC
Voltage
Magnitude
Calculation
|VS|
|VP| max
(Maximum Phase Voltage Magnitude)
(Maximum Phase-to-Phase Voltage Magnitude)
|VPP| max
VS
(Minimum Phase Voltage Magnitude)
|VP| min
(Minimum Phase-to-Phase Voltage Magnitude)
|VPP| min
(Negative-Sequence Voltage Magnitude)
|3V2|
(Zero-Sequence Voltage Magnitude)
|3V0|
59S1P
|VS|
59S1D
0
59S1T
Synch Voltage Elements
59S2P
59S2D
0
59S2T
Relay
Word
Bits
59S2
59S1
59S1P, 59S2P, 59P1P, 59P2P,
59Q1P, 59Q2P, 59G1P, 59G2P =
Vnm =
Settings
Effective Nominal Voltage
When DELTA_Y := DELTA
59Q1D
0
59Q1T
59Q2D
0
59Q2T
59Q1P
|3V1|
59Q2P
59P1P • Vnm
|VPP| min
59P1D
0
59P1T
59P2P • Vnm
59P2D
0
59P2T
Relay
Word
Bits
59P1
59P2
59Q1
59Q2
3P59
|VPP| max
When DELTA_Y := WYE
59Q1D
0
59Q1T
59Q2D
0
59Q2T
59Q1P
|3V2|
59Q2P
59P1P • Vnm
|VP| min
59P1D
0
59P1T
59P2P • Vnm
59P2D
0
59P2T
Relay
Word
Bits
59P1
59P2
59Q1
59Q2
3P59
59G1D
0
59G1T
59G2D
0
59G2T
59G1P
|3V0|
59G2P
59G1
59G2
|VP| max