GE D60 Instruction Manual page 637

CHAPTER 9: THEORY OF OPERATION
• AB phase element — (I
A
• BC phase element — (I
B
• CA phase element — (I
C
• A ground element — I
A
• B ground element — I
B
• C ground element — I
C
The limit angle of the comparator is adjustable, enabling the user to shape the characteristic as an mho or a lens as shown
in the figure. As explained in the Memory Polarization section, the memory-polarized mho characteristic has an excellent
directional integrity built-in.
9.1.3.3 Non-directional mho characteristic
The non-directional mho characteristic is achieved by checking the angle between
• AB phase element — (I
A
• BC phase element — (I
B
• CA phase element — (I
C
• A ground element — I
A
• B ground element — I
B
• C ground element — I
C
9.1.3.4 Mho reactance characteristic for directional applications
The reactance characteristic is achieved by checking the angle between
• AB phase element — (I
A
• BC phase element — (I
B
• CA phase element — (I
C
• A ground element — I
A
• B ground element — I
B
• 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.
9.1.3.5 Quadrilateral reactance characteristic for directional applications
The quadrilateral reactance characteristic is achieved by checking the angle between
• AB phase element — (I
A
D60 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
– I ) × Z – (V – V ) and (V
B A B A
– I ) × Z – (V – V ) and (V
C B C
– I ) × Z – (V – V ) and (V
A C A C
× Z + I_0 × K0 × Z + I × K0M × Z – V
G
× Z + I_0 × K0 × Z + I × K0M × Z – V
G
× Z + I_0 × K0 × Z + I × K0M × Z – V
G
Figure 9-1: Mho (left) and lens (right) characteristics
) × Z – (V
– I – V ) and (V
B A B A
– I ) × Z – (V – V ) and (V
C B C
) × Z – (V
– I – V ) and (V
A C A C
× Z + I_0 × K0 × Z + I × K0M × Z – V
G
× Z + I_0 × K0 × Z + I × K0M × Z – V
G
× Z + I_0 × K0 × Z + I × K0M × Z – V
G
– I ) × Z – (V – V ) and (I
B A B A
) × Z – (V
– I – V ) and (I
C B C B
– I ) × Z – (V – V ) and (I
A C A C
× Z + I_0 × K0 × Z + I × K0M × Z – V
G
× Z + I_0 × K0 × Z + I × K0M × Z – V
G
× Z + I_0 × K0 × Z + I × K0M × Z – V
G
– I ) × Z – (V – V ) and (I
B A B A
– V )_1M
B
– V )_1M
B C
– V )_1M
A
and V _1M
A A
and V _1M
B B
and V _1M
C C
) × Z
– V ) – (I – I
B A B REV
– V ) – (I – I ) × Z
B C B C REV
) × Z
– V ) – (I – I
A C A REV
and V – (I × Z
A A A REV
× Z
and V – (I
B B B REV
and V – (I × Z
C C C REV
– I ) × Z
B
) × Z
– I
C
– I ) × Z
A
and I_0 × Z
A
and I_0 × Z
B
and I_0 × Z
C
– I ) × Z
B
DISTANCE ELEMENTS
+ I_0 × K0 × Z + I × K0M × Z
REV G
+ I_0 × K0 × Z × K0M × Z
+ I
REV G
+ I_0 × K0 × Z + I × K0M × Z
REV G
)
REV
)
REV
)
REV
9
9-3