2-34 Relay Element Settings
Date Code 20020206 SEL-300G Instruction Manual
78FWD: Forward Reach
78REV: Reverse Reach
X'd: Generator Transient Reactance
Xt: Transformer Reactance
ZS: System Impedance
M-N: Total Impedance Between
Generator and System
S-S': Perpendicular Bisector of M-N
α
: Angle of Separation Between
Generator and System
Measured at 78R2
γ
: Angle of Separation Between
Generator and System
Measured at 78R1
78REV
–78R1 –78R2 78R2 78R1
78FWD
α
γ
S'
R
RR
R
S
N
Zs
DWG: M300G248b
Xt
Xd'
M
X
XX
X
78R2
Pickup
78R1
Pickup
78R1
Pickup
78R2
Pickup
Figure 2.49: Double Blinder Typical Settings
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