GE D30 Instruction Manual page 328
Line distance
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- Instruction manual (686 pages) ,
- Communications manual (532 pages) ,
- Instruction manual (646 pages)
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8.1 DISTANCE ELEMENTS
= 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
8
b) MHO PHASE A TO GROUND ELEMENT (BEFORE MEMORY EXPIRES)
× Z + I_0 × K0 × Z + I
I
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°
•
•
Zero-sequence directional difference angle = | 19.8° – 0.0° | = 19.8° < 75°
•
Negative-sequence directional difference angle = | 19.8° – 0.0° | = 19.8° < 75°
Fault-type comparator difference angle = | 19.8° – 19.8° | = 0.0° < 50°
•
All four comparators and the overcurrent supervision are satisfied.
The MHO phase A ground element will operate for this fault.
c) MHO PHASE A TO GROUND ELEMENT (AFTER MEMORY EXPIRES)
After the memory expires, the relay checks the actual positive-sequence voltage and compares it with 10% of the nominal
voltage:
| V
_1 | = 58.83 V > 0.1 × 69.28 V
A
After the memory expires the relay will use the actual voltage for polarization.
I
× Z + I_0 × K0 × Z + I
A
V
_1
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° – (–2.1°) | = 1.8° < 75°
•
Reactance difference angle = | –3.9° – 19.8° | = 23.7° < 75°
•
Zero-sequence directional difference angle = | 19.8° – (–2.1°) | = 21.9° < 75°
•
Negative-sequence directional difference angle = | 19.8° – (–2.1°) | = 21.9° < 75°
•
Fault-type comparator difference angle = | 19.8° – 19.8° | = 0.0° < 50°
•
All four comparators and the overcurrent supervision are satisfied.
The Zone 1 MHO phase A ground element will operate for this fault.
•
Zero-sequence directional difference angle for Zones 2 through 3 (phase A) = | 19.8° – 8.4° | = 11.4° < 90°.
Zones 2 through 3 phase A ground elements will pick-up, time-out and operate.
d) MHO AB PHASE ELEMENT
) × Z – (V
(I
– I
– V
A
B
A
B
(V
– V
)_1M
A
B
) × Z
(I
– I
A
B
8-8
× 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°
× K0M × Z – V
= 103.33 V ∠–3.9°
G
A
= 58.83 V ∠–2.1°
= 1.37 V ∠19.8°
= 19.11 V ∠19.8°
= 1.37 V ∠19.8°
= 88.65 V ∠–78.7°
)
= 112.08 V ∠30.0°
= 103.50 V ∠–21.2°
D30 Line Distance Relay
8 THEORY OF OPERATION
GE Multilin
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