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9.1 DISTANCE ELEMENTS
Distance Reach: 14 Ω
Left Blinder Reach: 5 Ω
Distance RCA: 88°
Left Blinder RCA: 88°
Polarizing Current: Zero-sequence
Non-Homogeneity Correction Angle: 3°
Directional RCA: 88°
Z0/Z1 Magnitude: 4.55
Overcurrent supervision: 3 A
Z0/Z1 Angle: –12°
Distance Comparator limit angle: 75°
Z0M/Z1 Magnitude: 0
Directional Comparator limit angle: 75°
Assume the following signals are injected to the relay:
= 64.71 V ∠0.0° (pre-fault)
V
A
= 25.43 V ∠–19.9°
V
A
= 80.22 V ∠–133.5°
V
B
= 77.33 V ∠135.7°
V
C
= 4.47 A ∠–107.8°
I
A
= 2.92 A ∠68.9°
I
B
= 2.93 A ∠–51.1°
I
C
Based on the entered setting the relay calculates:
K0 = 3.58 ∠–15.2°
K0M= 0
Z
= 14.00 Ω ∠88°
Z
= 1 Ω ∠88°
D
Z
= 9.99 Ω ∠−2°
R
Z
= 4.99 Ω ∠178°
L
For the assumed steady-state injection the relay calculates:
= 58.83 V ∠–2.1°
V
_1
A
= 64.71 V ∠0.0°
V
_1M
A
= 1.37 A ∠–68.2°
I_0
= 1.37 A ∠–68.1°
I
_2
A
= 29.18 V ∠8.4°
–V_0
= 93.35 V ∠32.0°
(V
–V
)_1
A
B
= 112.08 V ∠30.0°
(V
–V
)_1M
A
B
= 7.39 A ∠–109.1°
I
–I
A
B
b) MHO PHASE A TO GROUND ELEMENT (BEFORE MEMORY EXPIRES)
× Z + I_0 × K0 × Z + I
I
9
A
V
_1M
A
_2 × Z
I
A
D
I_0 × Z
I_0 × Z
D
•
Overcurrent supervision: | 3 × I_0 | = 4.09 A > 3 A
Mho difference angle = | –3.9° – 0° | = 3.9° < 75°
•
Reactance difference angle = | –3.9° – 19.8° | = 23.7° < 75°
•
9-8
× K0M × Z – V
= 103.33 V ∠–3.9°
A
A
= 64.71 V ∠0.0°
= 1.37 V ∠19.8°
= 19.11 V ∠19.8°
= 1.37 V ∠19.8°
D30 Line Distance Protection System
9 THEORY OF OPERATION
GE Multilin
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