Schweitzer Engineering Laboratories SEL-749M - Figure 4.13 Undervoltage Element Logic; Figure 4.14 Overvoltage Element Logic

4.25
Date Code 20080918 Instruction Manual SEL-749M Relay
Protection and Logic Functions
Voltage-Based Protection
Figure 4.13 Undervoltage Element Logic
Figure 4.14 Overvoltage Element Logic
27P1P • Vnm
|VP|
27P1D
0
27P1T
When DELTA_Y := WYE
When DELTA_Y := DELTA
27P2P • Vnm
27P2D
0
27P2T
27P1D
0
27P1T
27P2D
0
27P2T
Relay
Word
Bits
27P1P • Vnm
|VPP|
27P2P • Vnm
Relay
Word
Bits
VAB or VA
VBC or VB
VCA or VC
Voltage
Magnitude
Calculation
|VP|
|VPP|
(Minimum Phase Voltage Magnitude)
(Minimum Phase-to-Phase Voltage Magnitude)
27P1P, 27P2P =
Vnm =
Settings
Effective Nominal Voltage
27P1P
27P2P
27P1P
27P2P
59P1P • Vnm
|VP|
59P1D
0
59P1T
59P2P • Vnm
0
59P2D
59P2T
59P1D
0
59P1T
0
59P2D
59P2T
Relay
Word
Bits
When DELTA_Y := WYE
When DELTA_Y := DELTA
59P1P • Vnm
|VPP|
59P2P • Vnm
59P1P, 59P2P =
Vnm =
Settings
Effective Nominal Voltage
59P1P
59P2P
59P1P
59P2P
VAB or VA
VBC or VB
VCA or VC
Voltage
Magnitude
Calculation
|VP|
|VPP|
(Maximum Phase Voltage Magnitude)
(Maximum Phase-to-Phase Voltage Magnitude)
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