GE D30 series Instruction Manual page 409

9 THEORY OF OPERATION
X
MHO CHARACTERISTIC
c) NON-DIRECTIONAL MHO CHARACTERISTIC
The non-directional mho characteristic is achieved by checking the angle between:
• AB phase element: (I – I
A
• BC phase element: (I – I
B
• CA phase element: (I – I
C
• A ground element:
 Z + I_0  K0  Z + I
I
A G
• B ground element:
 Z + I_0  K0  Z + I
I
B G
• C ground element:
 Z + I_0  K0  Z + I
I
C G
d) MHO REACTANCE CHARACTERISTIC FOR DIRECTIONAL APPLICATIONS
The reactance characteristic is achieved by checking the angle between:
• AB phase element: (I – I
A
• BC phase element: (I – I
B
• CA phase element: (I – I
C
 Z + I_0  K0  Z + I
• A ground element: I
A
 Z + I_0  K0  Z + I
• B ground element: I
B
 Z + I_0  K0  Z + I
• C ground element: I
C
If the mho characteristic is selected, the limit angle of the comparator is adjustable concurrently with the limit angle of the
mho characteristic, resulting in a tent shape complementing the lens characteristic being effectively applied.
e) QUADRILATERAL REACTANCE CHARACTERISTIC FOR DIRECTIONAL APPLICATIONS
The quadrilateral reactance characteristic is achieved by checking the angle between:
• AB phase element: (I – I
A
• BC phase element: (I – I
B
• CA phase element: (I – I
C
 Z + I_0  K0  Z + I
• A ground element: I
A
 Z + I_0  K0  Z + I
• B ground element: I
B
 Z + I_0  K0  Z + I
• C ground element: I
C
GE Multilin
Reach setting
Comparator angle setting= 90
R
837715A2.CDR
Figure 9–1: MHO AND LENS CHARACTERISTICS
)  Z – (V
– V ) and (V
B A B A
)  Z – (V
– V ) and (V
C B C
)  Z – (V
– V ) and (V
A C A
 K0M  Z – V
and V – (I
A A
 K0M  Z – V
and V – (I
B B
 K0M  Z – V
and V – (I
C C
)  Z – (V
– V ) and (I
B A B A
)  Z – (V
– V ) and (I
C B C B
)  Z – (V
– V ) and (I
A C A C
 K0M  Z – V
G
 K0M  Z – V
G
 K0M  Z – V
G
)  Z – (V
– V ) and (I
B A B A
)  Z – (V
– V ) and (I
C B C B
)  Z – (V
– V ) and (I
A C A C
 K0M  Z – V
G
 K0M  Z – V
G
 K0M  Z – V
G
D30 Line Distance Protection System
X
LENS CHARACTERISTIC
)  Z
– V ) – (I – I
B A B REV
)  Z
– V ) – (I – I
B C B C REV
)  Z
– V ) – (I – I
C A C A REV
 Z + I_0  K0  Z
A REV REV
 Z + I_0  K0  Z
B REV REV
 Z + I_0  K0  Z
C REV REV
)  Z.
– I
B
)  Z.
– I
C
)  Z.
– I
A
I_0  Z.
and
A
I_0  Z.
and
B
I_0  Z.
and
C
)  Z.
– I
B
)  Z.
– I
C
)  Z.
– I
A
(j  I_0 or j  I_2A)  e
and
A
(j  I_0 or j  I_2B)  e
and
B
(j  I_0 or j  I_2C)  e
and
C
9.1 DISTANCE ELEMENTS
Reach setting
Comparator angle setting < 90
R
837714A2.CDR
 K0M  Z
+ I )
G REV
 K0M  Z
+ I )
G REV
 K0M  Z
+ I )
G REV
j
.
j
.
j
.
9
9-3