4.52
SEL-787 Relay
Instruction Manual
Date Code 20081022
Protection and Logic Functions
Voltage-Based Protection
Figure 4.29
Undervoltage Element Logic
Figure 4.30
Overvoltage Element Logic
27P1P
|VP|
27P1D
0
27P1T
When DELTA_Y := WYE
When DELTA_Y := DELTA
27P2P
27P2D
0
27P2T
27P1D
0
27P1T
27P2D
0
27P2T
Relay
Word
Bits
27P1P
|VPP|
27P2P
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)
59P1P
|VP|
59P1D
0
59P1T
When DELTA_Y := WYE
When DELTA_Y := DELTA
59P2P
59P2D
0
59P2T
59P1D
0
59P1T
59P2D
0
59P2T
Relay
Word
Bits
59P1P
|VPP|
59P2P
Relay
Word
Bits
VAB or VA
VBC or VB
VCA or VC
Voltage
Magnitude
Calculation
|VP|
|VPP|
(Maximum Phase Voltage Magnitude)
|3V2|
(Negative Sequence Voltage Magnitude)
(Maximum Phase-to-Phase Voltage Magnitude)
59P1P, 59P2P, 59Q1P, 59Q2P = Settings
59Q1P
|3V2|
59Q1D
0
59Q1T
When DELTA_Y := WYE or DELTA
59Q2P
59Q2D
0
59Q2T
Relay
Word
Bits
Summary of Contents for SEL-787
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